HastingsZidana AND Lake Malawi Biodiversity:

Jawless evolution explained

2010-10-22T11:58:00.000-07:00

With all respect to the author of this research and article in Science, I would like to express my appreciation of what microRNA's have done in jawless vertebrates. They have managed to tip the scale of mono and paraphyl to one side.

This may be the way forward in in our closely related cichlids, microRNA's may be able to decipher the relationships.

Hastings
========

Genetic evidence is laying to rest a long-standing argument over the evolution of jawless vertebrates -- hagfish and lampreys -- and providing insights regarding the common ancestor of all vertebrates.

For years, biologists have debated the origins of jawless vertebrates -- molecular biologists have argued that molecular evidence shows they are each other's closest relatives, while morphologists maintained that detailed anatomical features suggest lampreys were more closely related to jawed vertebrates.

In the most recent study, published Monday (18 October) in Proceedings of the National Academy of Sciences (PNAS), scientists on opposite sides of the argument looked at microRNA data, and found jawless vertebrates are indeed monophyletic, meaning they evolved from a common ancestor not shared by jawed vertebrates.

"I was staggered by this paper," said Philippe Janvier, a paleontologist at the Muséum National d'Histoire Naturelle in Paris, France, and a long time supporter of the idea that lampreys were more closely related to jawed vertebrates. "It's very hard for me to recognize that I've been wrong in my assumption," said Janvier, who did not participate in the research, but this paper provides "very, very strong support for the monophyly -- the common origin of lampreys and hagfishes apart from the origin of the jawed vertebrates."

Biologists originally classified lampreys and hagfish (cyclostomes) as part of a single group due to their gross anatomical similarities -- they were both eel-like creatures that lacked jaws. But more detailed morphological analyses in the 1970s suggested that lampreys were actually more closely related to jawed vertebrates, and hagfish were more primitive. This idea dominated the field until the early 1990s, when molecular evidence once again placed lampreys and hagfish together on the evolutionary tree. Over the next two decades, more and more molecular data emerged to support this monophyly hypothesis, but many morphologists continued to argue that lampreys were more similar to jawed vertebrates.

To resolve the debate, paleontologist Kevin Peterson of Dartmouth College and his colleagues turned to a new source of data -- microRNA. They created small RNA libraries for two different lamprey species, a hagfish, and a catshark (a jawed vertebrate). The team found all but two of the 46 miRNAs found in lampreys and jawed vertebrates in hagfish as well. Furthermore, they found four miRNA families unique to hagfish and lampreys, supporting the idea that the two groups are monophyletic.

"This adds a third type of data, [and] it does come down firmly on the side of cyclostome monophyly," said zoologist Sebastian Shimeld of the University of Oxford, who was not involved in the work.

This was no surprise to Peterson, who was already convinced of this conclusion by the molecular data. But his colleague and coauthor Phil Donoghue of the University of Bristol had been a strong proponent of the opposing view. Upon seeing the miRNA results, he decided to reanalyze the seemingly contradictory morphological data. Compiling all the data previously used to support the paraphyly hypothesis, that lampreys should be lumped with jawed vertebrates, and eliminating obsolete or inaccurate data, the analysis revealed inconclusive results.

"Lo and behold there really is no signal for paraphyly in phylogeny," Peterson said. Between the molecular data, the new miRNA analysis, and "especially with Phil's reanalysis of the morphology, I think you'd be hard pressed to assert strongly that cyclostomes are not monophyletic."

The results could indicate that the common ancestor to vertebrates is more complex than previously believed, Peterson added. If lampreys were more closely related to jawed vertebrates, and hagfish were basal to both groups, one could imagine "a successive building of the vertebrate body plan," Peterson explains -- "you start simple and then you make it more complex." If, on the other hand, lampreys are more closely related to hagfish, the last common ancestor of vertebrates most likely had all the derived characters still found in lampreys and jawed vertebrates, and hagfish simply lost some of these traits after they split from lampreys.

"I think [this study] is the tipping point where the vast majority of new researchers and some of the old morphologists will start to believe" that lampreys and hagfish form a single group, said evolutionary biologist Jon Mallatt of Washington State University, who did not participate in the research.

A.M. Heimberg, et al., "microRNAs reveal the interrelationships of hagfish, lampreys, and gnathostomes and the nature of the ancestral vertebrate," PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1010350107, 2010.

Read more: Jawless evolution explained - The Scientist - Magazine of the Life Sciences http://www.the-scientist.com/news/display/57752/#ixzz137Ev5y83

MUTATIONS RESPONSIBLE FOR ENVIRONMENTAL ADAPTATIONS

2009-11-04T12:48:00.000-08:00

MUTATIONS RESPONSIBLE FOR ENVIRONMENTAL ADAPTATIONS

While my blog is rooted on Lake Malawi cichlids biodiversity, sometimes I find stories which are indirectly related to the issue of rapid radiation of Lake Malawi cichlids. As we may all know the puzzle in cichlid evolution is to solve the oring of this stunning biodiversity of Lake Malawi. Among the factors responsible for this puzzle are mate choice basing on the male breeding colour morphs. Today, the study in bacteria has managed to locate the mutations which are responsible for phenotypic changes due to environment. In simplistic sense, think of colour morphs in cichlids and water levels or environment or geographic locations in Lake Malawi, is it possible to indetify the mutations responsible?? Think of red tops (P. zebra), blue tops (P. zebra), blue black tops (P. zebra) and C. afra. Is it possible to locate the mutations responsible??

Now read on the story below:
==============================

Researchers for the first time have tracked the specific genetic mutations -- occurring over just a few generations -- that allow bacteria to respond to environmental changes, they report online in Nature today (November 4).

"We showed how evolution happens in real time," said Hubertus Beaumont, a biologist from Leiden University in the Netherlands and first author on the study.

Studies have shown bacteria and other organisms can switch back and forth between phenotypes to better survive in new environments. For instance, Beaumont said, many bacteria switch their surface antigens when invading a host, so they can avoid being attacked, and certain desert plants are programmed to germinate seeds at random time intervals, increasing their chances of encountering rain. "This bet-hedging strategy is very simple, but captures the essence of evolution." Beaumont said. "Natural selection in these uncertain environments causes an organism to evolve protective traits." Exactly how such phenotypic adaptability emerges, however, was unknown.

In order to observe how bet-hedging evolves, Beaumont and his colleague Paul Rainey at Massey University in New Zealand observed Pseudomonas fluorescens, a common rod-shaped bacterium, in a new type of environment. They already knew that the bacteria grow well in a test tube that's shaken manually or in an incubator that allows oxygen to circulate in the culture. So instead of shaking the test tube, a condition to which the bacteria are well-adapted, the researchers watched the bacteria grow in non-shaken test tubes.

As expected, some of the bacteria adapted to the novel environment, forming colonies with an advantageous "wrinkly" morphology as opposed to the ancestral bacteria, which grew smoothly. The team identified these new colony types in the test tube and transferred them to fresh tubes, repeating this process 15 times to select for the new variations. Eventually, the bacteria evolved the ability to rapidly switch their phenotypes between the "wrinkly" and "smooth" cell-types to prepare themselves to cope with the different environments.

"I find these results really intriguing," said Martin Ackermann, an environmental microbiologist at Eidgenössische Technische Hochschule Zurich (or ETH Zurich) in Switzerland who was not involved in the research. "It is amazing to see that phenotypic switching can evolve so rapidly, in the course of a just a few rounds of selection. As far as I know, this has not been observed before."

Beaumont and Rainey then sequenced the evolved bacterial genome and found all the mutations that had arisen and that might have contributed to this new trait. The team identified nine mutations distinguishing bet-hedgers from their ancestors. They pinpointed one specific mutation as the one which allows the phenotype to switch back and forth between different morphologies, while the other mutations, they found, were essential for growing the new type of bacteria.

"It's yet another beautiful study at multiple levels from Paul Rainey's team," said Richard Lenski, a microbial ecologist at Michigan State University who didn't participate in the research, in an email. "This is a neat demonstration that the evolution of bet-hedging was contingent on other mutations that had occurred earlier in the lineage." These earlier changes improved the fitness of the bacteria at each stage.

"The results thus suggest that phenotypic switching is a strategy that can readily evolve," and may capture the earliest evolutionary solutions to life in fluctuating environments, Ackerman wrote in an email.

Malawi at the root of humankind 6 MYA

2009-10-23T11:43:00.000-07:00

Malawi could be the cradle of humankind-researcher

KARONGA, Malawi (Reuters) - The latest discovery of pre-historic tools and remains of hominids in Malawi's remote northern district of Karonga provides further proof that the area could be the cradle of humankind, a leading German researcher said.

Professor Friedemann Schrenk of the Goethe University in Frankfurt told Reuters that two students working on the excavation site last month had discovered prehistoric tools and a tooth of an hominid.

"This latest discovery of prehistoric tools and remains of hominids provides additional proof to the theory that the Great Rift Valley of Africa and perhaps the excavation site near Karonga can be considered the cradle of humankind," Schrenk said.

A hominid is a member of a family of primates which includes humans and their prehistoric ancestors.

The discovery was at Malema excavation site, 10 km (6 miles) from Karonga.

The site also contains some of the earliest dinosaurs which lived between 100 million and 140 million years ago and early hominids believed to have lived between a million and 6 million years ago.

He is leading a team of researchers from Europe and Africa to establish an African center for interdisciplinary studies on mammal and hominid evolution in the southern African nation.

Karonga is about 615 km (380 miles) north of the capital Lilongwe and is near the border with Tanzania.

Pheromones may not initiate sexual attraction and mating

2009-10-14T14:15:00.000-07:00

This story was taken from science magazine on as is basis, but found it interesting as I am working on mate choice of Lake Malawi cichlids as well. The role of chemical cues in cichlid mate choice has already being suggested but their relationship with the pheromeones (hydrocarbones) is yet to be told. The following study in drosophila has worked on such untouched components.

======= =========== ======== ========== ====== ========

Pheromones may not initiate sexual attraction and mating, as commonly believed, new research suggests. Instead, the chemical signals may help flies distinguish between different genders and species while choosing a mate, researchers report in this week's issue of Nature.

This is the first time a study has deciphered the chemical dialogue happening between flies as they mate," said Nicolas Gompel, a geneticist at the Institut de Biologie du Developpement de Marseille-Luminy in France, who was not involved with the research but wrote an accompanying commentary on the paper. "The research challenges the common belief that pheromones are essential to initiate courtship... and suggests that instead, [they] play a significant role in mate identification and selection."

Scientists have long understood that pheromones, hydrocarbons produced by an animal or insect that trigger reactions in another individual, play a role in mating. But they've been unable to identify the role of individual pheromones because the hydrocarbons are often secreted as blends, comprised of up to 30 molecules, and function in conjunction with other signals. In order to study individual pheromones, Jean-Christophe Billeter from the University of Toronto at Mississauga and his colleagues genetically engineered adult Drosophila melanogaster without oenocytes, cells that secret hydrocarbons. The oenocyte-less flies were "blank slates," said Joel Levine, a geneticist from the University of Toronto and coauthor of the study, allowing the team to imprint one pheromone at a time.

Because pheromones have been generally believed to stimulate mating, Billeter and his colleagues expected that flies lacking hydrocarbons would be sexually unappealing to males. To their surprise, quite the opposite happened: wild-type males were hyperattracted to oenocyte-less flies. The wild-type males also ignored gender, choosing to mate with both unscented males and females over other wild-types. These results led the researchers to conclude that pheromones may not stimulate mating, but may instead act to slow down male mating attempts to allow the female to assess her partner's suitability. They also concluded that hydrocarbons help flies distinguish between sexes.

Billeter and his colleagues then tested the effect of individual pheromones on mate selection and copulation attempts. Researchers treated unscented D. melanogaster with wild-type levels of cVA, a hydrocarbon males are known to coat on females to deter further mating attempts. As expected, cVA effectively created a "chemical chastity belt," said Gompel.

Researchers then treated unscented flies with 7,11-heptacosadiene (7,11-HD), a pheromone thought to act as an aphrodisiac for flies. Although 7,11-HD alone did not stimulate additional mating attempts, when applied over cVA, it helped diminish the inhibiting effect of the compound, allowing females to broadcast their mating availability. The findings suggested that mating doesn't depend on just one pheromone relaying a message of availability, but instead on a complex mixture of attractive and aversive signals.

7,11-HD also seemed to act as a species barrier in mating. Unscented D. melanogaster females treated with the hydrocarbon attracted males of the same species, but deterred D. simulans and D. yakuba males.

"It's neat that one hydrocarbon (7, 11-HD) acts both as an aphrodisiac to males of D. melanogaster and also as a key compound causing males of other closely related species in the genus to reject her," said Tristram Wyatt, an evolutionary biologist at the University of Oxford. "It's surprising at first sight, but perhaps it's another example of evolution resulting in simple solutions, two effects for one."

Billeter's study isn't the first time that the pheromone-less flies have been shown to be hyperattractive. Fabrice Savarit from the Universite Paris Sud and colleagues reported similar results in 1999. "One of the main differences between our study and Billeter's is his team was able to cleanly get rid of oenocytes," said Matthew Cobb, an evolutionary neurobiologist at the University of Manchester in England and coauthor of the 1999 study. "We produced pheromone-less flies in a roundabout way by overexpressing the UAS-tra transgene. Billeter's methodology is much more precise and reproducible." Billeter's study was also able to produce pheromone-less male flies, something Cobb's team failed to do.

Wyatt agreed, noting that the "blank canvas" flies will be invaluable "in further researching the neural circuits involved in sex and species recognition in these flies."

Cobb also noted that while hydrocarbons excreted by oenocytes may not initiate mating in flies, other pheromones might. In their 1999 study, Savarit and his colleagues noticed there was still a small amount of pheromones on their supposedly hydrocarbon-less female flies. Cobb noticed a similar trend in Billeter's data. "It seems even after they wiped out all the oenocytes in flies, there is a tiny -- we're talking less than 10 millivolts -- but significant amount of hydrocarbons still present," he said. "These might be ancestral pheromones, or not, but either way it is very intriguing."

Elevated genetic diversity in introduced populations of Cynotilapia afra

2009-10-01T16:32:00.000-07:00

Genetic variation in many invasive species shows little or no signs of a founder event, suggesting that high genetic diversity may facilitate establishment success. The rocky-shore, plankton-feeding cichlid fish Cynotilapia afra is endemic to Lake Malawi, but naturally absent from many suitable sites. In the 1960s, this species was introduced to the southern areas of the lake, presumably as a result of the aquarium fish trade. It has now become established on a number of rocky areas within the Lake Malawi National Park. Here, we analysed DNA sequence variation in the mitochondrial control region of six native and four introduced populations of C. afra, and three populations of the closely-related and hybridizing Pseudotropheus zebra. In contrast to previous studies of Lake Malawi rock dwelling cichlids, network analyses suggested that native populations of C. afra showed high levels of lineage sorting in mtDNA. Introduced populations showed higher sequence and haplotype diversity than their native counterparts. Our analyses suggested that the elevated gene diversity was largely attributed to the fact that the introduced C. afra populations were derived from several genetically distinct and geographically separate populations, and to a lesser extent because of introgressive hybridization with native P. zebra. The establishment and spread of C. afra may be partly because of its ability to occupy a vacant ecological niche, but it may also have been facilitated by its enhanced genetic diversity.

LATERAL LINE AS AN ADAPTATION TO FEEDING BAHAVIOUR

2009-06-22T14:27:00.000-07:00

We are all fascinated by the jaw morphology adaptation of Lake Malawi cichlids as one of the driving mechanism in their diversity. One of this months published studies has revealed the lateral line to be among the wonders of the feeding behaviour in cichlids.

Working on one of the peacock cichlids of the so called "Alunocara" group, it has been reported that their wide cavity lateral line is responsible for the efficiency of this species in getting food.

Three groups of fish were studied, one with normal cavity, another chemically deformed and last group feeding in the dark. The chemically deformed lateral line failed to ge their prey, while the other two hand their game on spot.

Let us know that this mechanism is widely spread among the deep sea fish, and for the peacocks to posses this adaptation within Lake Malawi system which is suggested to have clear waters and suppossedly clear feeding vision is one of the seven wonders in fish biology and the cichlid system as a whole.

As if this is not enough, on a lighter note this group of "Alunocara" is among the most expensive products of the aquarium trade despite having a wide distribution range within Lake Malawi.

The Lake Malawi biodiversity will never cease to amaze us!

WHATS NEXT THE CICHLIDS WE ARE WATCHING.

Hatchery breeding for reintroduction into Lake Malawi

2009-06-19T15:33:00.000-07:00

Evidence is increasing on the downside of captive breeding aimed for reintroduction into the wild. A study published in Biology Letters suggest that wild born offspring from hatchery raised Steelhead Trout parents has only 37% reproductive fitness as compared to 87% if only one of the parents was wild breed. These differences are still detected even if the fish have spent one generation in the wild.

Lake Malawi holds one of the stunning cichlid biodiversity in the world, however this biodiversity is believed to be only 1 to 2 million years old. In other words is still going through sysnthesis, thus most of the cichlids still interbreed naturally during a secondary contact. The results from the above mentioned study should tell us that one of our cards to mitigate for overfishing of the most sort Tilapia should not be hatchery raised ones, but reinforcement of the fishing season and fishing gear size.

If hatchery breed fingerlings are to be used in Chambo restoration plan, then genetic differences between them and wild types should be well studied. As far as I know the aquaculture stock at the moment may not be the best candidates for this exercise. Molecular studies have already revealed that the aqua stock has a mixed up gene pool, that is neither pure Chambo (O. karongae), nor Makakana (O. mossambicus) to mention a few.

All the evidence points us to one thing, Chambo restoration plan should be based on proper scientifc evidence not emotions or personnal gains if we are aiming to produce and really preserve the original (OK) gene pool, which is tasty and tender as claimed by the Lake shore crew.

On a lighter note, while my emphasis has been on the famous chambo, the same principle should also apply on the red listed Ntchila, Sanjika, Ningwi ect in river shire and its catchment.

Have a nice weekend.

THE SCHOOLING AND SHOALING FACTOR

2009-06-05T16:35:00.000-07:00

Have we ever asked why do fish move in groups aka schools or shoaling behavior.

No No No the sheep are best at it, when one makes it into the M1 road, yes in Malawi all of them will follow. But, why? If you can not answer this question by studying these mogastrics then that is why our study system the cichlids are the coolest. Yes they are the toughest they can tell you many of the amazing behaviour we have in animal kngdom.

A study published in Current Biology Journal on 29 th Jan 09, tells it all. The secrete is they do their social work best when they are in groups than go it alone stuff. So do not say I did not tell you, social insects also knows these best, ask the bees, fire ants, flying ants ect.

From a blog at the scientist web, here is what they had to say on stickle backs.

read on
==========

Nuts at dawn: Britain's squirrels fight for survival

2009-04-23T08:55:00.000-07:00

Deep in the heart of England's seemingly peaceful countryside, a fierce battle for survival is being waged between the domestic red squirrel, its tougher grey cousin -- and a new mutant arrival.
Where there were once 3.5 million red squirrels in Britain, only about 150,000 remain. About 75 percent of these live in the wild in Scotland, while most of the rest are protected in nature reserves in northern England.
A plethora of organisations comprising hundreds of members have sprung up in their support, and in recent months they have stepped up their efforts to check the cause of this slaughter -- the grey squirrel.
Imported from the United States in 1876 to populate country estates, the greys were larger and had thicker fur than their English cousins and quickly began to dominate -- so much so that in 1930, it became illegal to release them into the wild.
But the containment policy failed and the greys began to encroach on the reds' territory, with disastrous results.
The reds were less hardy than their American cousins -- they need more space and their food takes longer to ripen -- but it was the squirrel pox virus that did the most harm. Greys are immune, but it proves fatal for reds.
"It can take only one grey squirrel to introduce this virus to a local population of red squirrels, and then the virus can spread throughout the reds with devastating effect," says the group Save our Squirrels (SOS).
As a result, red squirrels -- viewed in the early 20th century as a pest to be hunted down and killed -- have been a protected species since 1981.
At the same time, the reputation of the greys, who now number about 2.5 million in England and Wales, gets worse and worse.
Some organisations believe in radical action. The Red Squirrel Protection Partnership (RSPP), in Northumberland in northern England, has a clear plan -- to trap and kill as many grey squirrels as possible.
According to the RSPP's website, 22,287 squirrels have been killed since January 2007, as supporters act with military-style precision. Some of these end up on the butcher's block or on restaurant menus.
"We only call ourselves the Red Squirrel Protection Partnership because if we called it the Grey Squirrel Annihilation League people might be a bit less sympathetic," supporter Baron Rupert Mitford told the Guardian newspaper.
Public organisations have so far shied away from such a radical solution but the tactic is gaining ground.
For example, the Saving Scotland's Red Squirrels project, launched in February by a coalition of Scottish groups, purports to protect the habitat of red squirrels and "control" the grey population.
A few timid voices defend the greys, however, noting they face a similar fate to the red squirrels at the hand of a new arrival -- the black squirrel.
These are the result of a genetic mutation of the grey squirrels and are spreading across Britain from East Anglia, where the greys were first introduced.
According to a study by Alison Thomas, a geneticist at Anglia Ruskin University in Cambridge, the black squirrel made up almost half the rodent population in some areas at the beginning of 2008.
"The estimate is about 25,000 (black squirrels) today, but the black mutation gene has a dominant aspect which explains their rapid increase," she told AFP.
With a thicker coat and a higher level of testosterone than either the red or grey squirrels, the black mutants have been dubbed the "super-squirrel" and are proving more attractive to females -- ensuring their population flourishes.

ECOLOGY, SEXUAL SELECTION, HYBRIDISATION AS SPECIATION MECHANISMS

2009-01-28T17:04:00.000-08:00

What? Who said we geographic isolation alone?

The article below has some insights on mechanisms involved in speciation. The high biodiversity of cichlid fishes in great Lake of Malawi is one of the many examples of organisms that have appreciated this mechanisms and produced the unspoken wonders of the world.

Just get a dive in rocky habitats of Cape Maclear, Nkhata Bay, Likoma and Monkey Bay just to mention a few localities and you will appreciate what we are trying to communicate here.

Do not say I did not tell you.
===============================================================

SEXUAL SELECTION AND SPECIATION
The following points are made by K. Kraaijeveld and A. Pomiankowski (Current Biology 2004 14:R419):1) When Charles Darwin (1809-1882) [1] proposed his theory of sexual selection he was concerned mainly with explaining the widespread occurrence of exaggerated sexual ornaments and courtship displays, as these traits could not easily be explained by natural selection. He also noted that taxonomic groups with more pronounced sexual ornaments tended to have more species. This suggests that sexual selection may elevate the rate at which populations diversify and give rise to new species. A new study [2] of female mate preferences in five populations of an East African cichlid species strongly supports the connection between sexual selection and speciation.2) With the surge of interest in sexual selection over the past few decades, the question of whether it can lead to speciation has also enjoyed renewed attention. A plethora of theoretical models have investigated the connection, and generally concluded that sexual selection can promote speciation (3). The main evolutionary mechanism proposed invokes the rapid coevolution of female mate preferences and male courtship traits, leading to reproductive isolation between groups of individuals. However, empirical evidence in support of the idea is scarce.3) An indirect way this idea has been tested involves looking across broad taxonomic groups for a link between the strength of sexual selection and species number. So far, the evidence from these studies has been conflicting. In birds for example, taxa with greater sexual differences in plumage color -- an indicator of sexual selection -- have higher species numbers compared to sister taxa subject to weaker sexual selection [4,5]. However, surveys in other groups (butterflies, mammals, and spiders) have failed to find such an association, and the positive result in birds has not been replicated in a recent reanalysis. It seems premature to conclude from this that speciation is independent of sexual selection. One reason for the lack of a strong linkage is that sexual selection may promote extinction as well as speciation, if it leads to the evolution of traits maladaptive to male and female survival. Another is that sexual selection can even retard speciation under certain conditions. So in the long term, species numbers may only loosely be connected to sexual selection.4) A more direct way of investigating the connection between sexual selection and speciation is to examine its action in closely related populations. Knight and Turner [2] attempted such a test using populations of the cichlid fish Pseudotropheus zebra from Lake Malawi. The cichlid fishes of the East African lakes, in particular Lake Victoria and Lake Malawi, are renowned for rampant speciation over a very brief period of time -- more than 1000 species have been generated in less than a million years. Some of this diversity is due to ecological specialization, facilitated by the "key innovation" of the cichlid pharyngeal jaw. But many closely related species show practically no differences except in male color, suggesting that sexual selection may be an important additional mechanism of speciation.
References (abridged):1. Darwin, C.R. (1871). The Descent of Man and Selection in Relation to Sex. (London: John Murray)2. Knight, M.E. and Turner, G.F. (2004). Laboratory mating trials indicate incipient speciation by sexual selection among populations of the cichlid fish Pseudotropheus zebra from Lake Malawi. Proc. R. Soc. Lond. B 271, 675-6803. Turelli, M., Barton, N.H., and Coyne, J.A. (2001). Theory and speciation. Trends Ecol. Evol. 16, 330-3434. Barraclough, T.G., Harvey, P.H., and Nee, S. (1995). Sexual selection and taxonomic diversity in passerine birds. Proc. R. Soc. Lond. B 259, 211-2155. Owens, I.P.F., Bennett, P.M., and Harvey, P.H. (1999). Species richness among birds: body size, life history, sexual selection or ecology?. Proc. R. Soc. Lond. B 266, 933-939

ON HABITATS AND ECOLOGICAL SPECIATION.
The following points are made by R. Ogden and R.S. Thorpe (Proc. Nat. Acad. Sci. 2002 99: 13612):1) Understanding speciation processes in rainforests is key to predicting changes in species number and planning conservation strategy (1). Ecological speciation due to divergent natural selection has emerged as an alternative theory to speciation in geographic isolation. Recent studies in support of an ecological gradient model of speciation in rainforests have shown morphological differences between habitats but have not tested for a reduction in gene flow (2,3) or have not reported such a reduction where it has been tested (3,4). Morphological variation along ecological gradients may indicate diversification, but speciation is not an inevitable consequence of population differentiation (5), and molecular evidence of reduced gene flow is needed to strengthen support for the theory of ecological speciation.2) The authors report a study in which molecular markers were used to examine the effects of allopatric divergence and habitat on levels of gene flow in the Caribbean lizard Anolis roquet. Three study transects were constructed to compare variation in microsatellite allele frequencies and morphology across phylogenetic and habitat boundaries in northern Martinique. Results showed reductions in gene flow to be concordant with divergent selection for habitat type. No evidence could be found for divergence in allopatry influencing current gene flow. Morphological data match these findings, with multivariate analysis showing correlation with habitat type but no grouping by phylogenetic lineage. The results support the ecological speciation model of evolutionary divergence, indicating the importance of habitats in biodiversity generation.References (abridged):1. Moritz, C. , Patton, J. L. , Schneider, C. J. & Smith, T. B. (2000) Annu. Rev. Ecol. Syst. 31, 533-5632. Schneider, C. J. , Smith, T. B. , Larison, B. & Moritz, C. (1999) Proc. Natl. Acad. Sci. USA 96, 13869-138733. Smith, T. B. , Schneider, C. J. & Holder, K. (2001) Genetica 112, 383-3984. Smith, T. B. , Wayne, R. K. , Girman, D. J. & Bruford, M. W. (1997) Science 276, 1855-18575. Magurran, A. E. (1998) Philos. Trans. R. Soc. London B 353, 275-286Proc. Nat. Acad. Sci.

HYBRIDS AND SPECIATION
The following points are made by Richard J. Abbott (Science 2003 301:1189):1) Why sex evolved and is maintained in most living organisms remains a key question in evolutionary biology (1). What is indisputable, however, is that sexual reproduction generates new gene combinations, some of which may render the organism better adapted to new environments. The range of different genotypes among offspring increases with the level of genetic divergence between parents. Therefore, matings between different species (that is, interspecific hybridization could potentially generate a vast range of different offspring genotypes, provided that the resulting hybrid zygotes develop and exhibit some fertility. For example, Rieseberg et al (2) describe how hybridization between two sunflower species generated offspring genotypes that are adapted to habitats very different from those occupied by the parents. This resulted in three diploid hybrid sunflower species that are ecologically isolated from each other and their progenitors. The Rieseberg et al findings provide proof that interspecific hybridization can be adaptive.2) In many plant groups, hybridization between different species is prevented by prezygotic barriers. Such barriers may arise when species have their own specific pollinator, occupy a habitat different from other species, or are spatially separate from other species. Under these conditions, postzygotic barriers manifested in the form of embryo abortion or low hybrid viability may be absent or weak. However, prezygotic barriers can be "leaky", especially when habitats are disturbed in some way, so hybrids are sometimes produced that are often sterile or exhibit reduced fertility. Such problems of low fertility can be overcome, either by chromosome doubling (allopolyploidy) or recombination (3), to produce a stable fertile hybrid that is reproductively isolated from its parents by a strong postzygotic barrier (4,5), and which is therefore regarded as a new species.3) Although postzygotic barriers are effective mechanisms of reproductive isolation, they present major obstacles to the establishment of a new hybrid species in the wild. Hybrids are born into populations comprising one or both parent species and will initially be represented as a minority component. Consequently, most matings by a fertile hybrid will be with a parent rather than another hybrid, and will result in the production of no offspring or sterile offspring. The hybrid therefore suffers from what is termed a "minority type disadvantage" (4). It can escape from this predicament by evolving a prezygotic barrier that prevents it from mating with its parents. This can be achieved through uniparental reproduction (asexual reproduction or selfing), by flowering earlier or later, by attracting a different pollinator, by occupying a different habitat (ecological isolation), or through spatial isolation due to geographical separation after dispersal (3). Ecological or spatial isolation will also enable a hybrid to avoid any adverse effects of interspecific competition with a parent.References (abridged):1. S. A. West et al., J. Evol. Biol. 12, 1003 (1999)2. L. H. Rieseberg et al. Science 301, 1211 (2003)3. V. Grant, Plant Speciation (Columbia Univ. Press, New York, ed. 2, 1981) 4. D. A. Levin, The Role of Chromosomal Change in Plant Evolution (Oxford Univ. Press, Oxford, 2002)5. J. F. Gutierrez-Marcos et al., Philos. Trans. R. Soc. London Ser. B 358, 1105 (2003)

COLOUR MEDIATED SPECIATION IN CICHLIDS

2008-10-30T11:27:00.000-07:00

I read the article and think of colour polmorphism evolution rather than speciation. But as everyboyd has said the results are interesting and the study was well set.

Hastings

VIEWS FROM THE SCIENTIST

Capturing the eye of a potential mate is the first step in propagating a species. But can the way a female sees males of a certain color lead a single species of fish to split into two? A study published this week in Nature suggests two species of cichlid fish -- one red and one blue -- may have arisen from the female mating preference for males she is best able to see. "We've wanted since Darwin to understand how species originate," said Karen Carleton, a biologist at the University of Maryland and co-author of the study. "This is one of first times we've been able to understand from the molecular level to the fish to the environment to get the whole picture." Researchers have long believed that geographic isolation was the primary force behind the evolution of a single species into two reproductively incompatible groups, yet, as lead author and evolutionary biologist Ole Seehausen, found in Lake Victoria in eastern Africa, the red and blue cichlids were separated by as little as 15 meters of water. Earlier studies showed that red cichlids live closer to the lake bottom, while the blue cichlids frequent more shallow waters, and the females (dressed in muted yellow fins) chose the most vibrantly colored of the males at their water depth. To understand factors driving female mating preference, Seehausen's team examined light gradients in different depths of water and the opsin gene, which produces a protein that detects color. "We knew about the mating preferences [in cichlids] but we did not know where in the process the divergent evolution at the opsin gene locus occurred," Seehausen said. The researchers genotyped the opsin gene of cichlids from five islands in Lake Victoria and identified the gene's variants in the red and blue cichlids. They then expressed the genes in vitro, showing that the protein product of each variant absorbed light at a different wavelength: in red cichlids, the protein was more sensitive to red light, while in blue cichlids it was more sensitive to blue light. Meanwhile, light gradient data showed blue light was more easily visible in shallow water and red light in deep water. The findings suggest that natural selection in each species' visual system toward red- or blue- sensitivity, which allows cichlids to best navigate their environment, may also drive females to the males they are best able to see. "The evidence shows that in a heterogeneous environment, where different conditions prevail along a gradient, selection is strong enough to create two species," said Seehausen. Trevor Price, who studies the evolution of color patterns in birds at the University of Chicago, said he's excited about Seehausen's model, but stressed that more evidence is needed to "make the connection that female color vision is driving speciation." Females with the red-biased and blue-biased opsin variants generated from controlled crosses in Seehausen's lab demonstrated no preference between red and blue males in the lab tank. "These findings suggests the opsin gene themselves are not causing mating preference," Seehausen said. "It could be the interaction of visual gene and ambient lighting." Seehausen said his group plans to look for additional genes and traits involved in mate choice in cichlids in order to understand how these interact with the adaptation of the visual system.

THE HUMAN DIVERSITY MAY BE COMING TO A HALT

2008-10-07T04:33:00.000-07:00

Hi

Here is another mind blowing article on the componets that determine the human
diversity and indeed all living creatures on our planet earth.

The people on the driving seat are warning that,while these processes may be still at
work in other organism just like our super radiation of Lake Malawi cichlid fish, the story
is different in human populations.

However, as we live in an ever changing universe the story may not be as simple as we
may see it. In mind is the global warming issue. With most of the areas on earth
claimed to be at risk, the human population may be heading for a revolution of
their diversity in the near or distant future. The effective population size might
be at risk and random drift will play its part, thus reshuffling the diversity as
well.

All in all its intersting and informative to know how our diversity is struggling at
the moment.

Have a good time read on the article below.

Hastings
========

Press Assoc. - Tuesday, October 7 04:21 am

Human evolution is grinding to a halt, according to a leading genetics expert.

The gloomy message from Professor Steve Jones is: this is as good as it gets.
Prof Jones, from the Department of Genetics, Evolution and Environment at University College London, believes the mechanisms of evolution are winding down in the human race.
At least in the developed world, humans are now as close to utopia as they are ever likely to be, he argues. Speaking at a UCL Lunch Hour Lecture in London, Prof Jones said there were three components to evolution - natural selection, mutation and random change.

He said: "In ancient times half our children would have died by the age of twenty. Now, in the Western world, 98% of them are surviving to the age of 21. Our life expectancy is now so good that eliminating all accidents and infectious diseases would only raise it by a further two years. Natural selection no longer has death as a handy tool."

Mutation rate was also slowing down, he said. Although chemicals and radioactive pollution could cause genetic changes, one of the most important mutation triggers was advanced age in men. "Perhaps surprisingly, the age of reproduction has gone down - the mean age of male reproduction means that most conceive no children after the age of 35," said Prof Jones. "Fewer older fathers means that if anything, mutation is going down."

Random alterations to the human genetic blueprint were also less likely in a world that had become an ethnic melting pot, according to Prof Jones.

He said: "Humans are 10,000 times more common than we should be, according to the rules of the animal kingdom, and we have agriculture to thank for that. Without farming, the world population would probably have reached half a million by now - about the size of the population of Glasgow.

"Small populations which are isolated can change - evolve - at random as genes are accidentally lost. Worldwide, all populations are becoming connected and the opportunity for random change is dwindling. History is made in bed, but nowadays the beds are getting closer together. Almost everywhere, inbreeding is becoming less common. In Britain, one marriage in fifty or so is between members of a different ethnic group, and the country is one of the most sexually open in the world. We are mixing into a global mass, and the future is brown."

He added: "So, if you are worried about what utopia is going to be like, don't; at least in the developed world, and at least for the time being, you are living in it now."

Conservation Of Freshwater Fish Biodiversity: A Challenge For The Countries Of The South

2008-09-30T09:13:00.000-07:00

ScienceDaily (Mar. 27, 2008) — Scientists at the Institut de Recherche Pour le Développement (IRD) and colleagues* have made the first global-scale analysis of the processes leading to freshwater fish invasion in river basins. This phenomenon affects most river ecosystems of countries of the Northern hemisphere. However, in the context of economic growth developing countries are now experiencing, their river basins, home to the greater part of freshwater fish biodiversity, are at risk of the same fate unless vigilance is applied.
Humans have regularly been introducing exotic species into natural environments in order to provide for their nutritional necessities or meet less indispensable purposes such as horticulture, fishing or hunting. However, the particular environments are not always adapted for hosting new arrivals. Past introduction attempts, such as that of wild rabbit into Australia or brown fario trout into Southern hemisphere water courses, led to an awareness that these different species, qualified by scientists as none-native, have the power to upset an ecosystem.
The 2002 Convention on Biodiversity recognized that the species introductions can cause regression of biological diversity, following destruction of natural habitats. Although it has long seemed likely that human activity plays a major role in such effects, no scientific study had yet yielded measurements of its involvement at planetary scale for a given group of species. An international research team comprising IRD, CNRS and University of Toulouse scientists recently published a study that gave the first real demonstration that human activity is the main driving factor behind the establishment of exotic fish species populations in river ecosystems.
Examination of data on presence of around 10,000 freshwater fish in 1055 river basins covering both 80% immersed lands and 80% of globally recorded freshwater fish species allowed identification of seven species-invasion hot-spots: the Pacific coast of North America and Central America, Patagonia, southern and western Europe, South Africa and Madagascar, central Asia, the South of Australia and New Zealand. These regions are characterized by river basins where non-native species make up more than one quarter of the freshwater fish species recorded. Moreover, they are superimposed on biodiversity hot-spots which correspond to geographical zones a strong endemism rate and a very high total number of species.
The team also sought to determine the extent of the relative influence of the particular characteristics of each ecosystem and human activities on the diversity of the non-native fish species. Three hypotheses were tested: the "biotic resistance", "biotic acceptance" and "human activity". The first suggests that a high diversity of freshwater fish in the host ecosystem acts as a barrier to the establishment of non-native fish specie populations.
The second postulates conversely that, for a given ecosystem, non-native species diversity follows that of native species because favourable ecological conditions for the latter are also suitable for the newly arrived species. As for the third, it takes account of the different indicators at river-basin scale (gross domestic product, percentage of land urbanized, population density), that can yield determination of the relation between anthropic pressure and non-native species diversity.
The three hypotheses' relative weight was measured using statistical methods. For the whole set of river basins investigated, the environmental conditions of fluvial ecosystems were found to have practically no influence on the exotic species diversity. On the contrary, it is the human factors, and especially the intensity of economic activities --measured by the GDP, which determine the number of non-native species present in a river basin.
These results thus suggest that the economic development foreseen in the developing countries should be accompanied by a rise in the number of non-native freshwater fish species. Given that biological invasions are considered as one of the main causes of biodiversity loss, such a scenario would probably be detrimental to the aquatic biodiversity conservation of these regions. This study indicates that exceptional river ecosystems, like the Amazon Basin in South America or that of the Congo in central Africa, are still hardly affected by species introduction.
For example, no more than 1% of the 3000 species of fish recorded in the River Amazon are non-native species. Just as a considerable number of countries of the South are seeing their economic growth take off, this kind of study should be useful in the future for setting up an effective watch system for the surveillance of the exotic species colonizing the most biodiversity-rich natural environments and make it possible to apply the principle of precaution before they become invasive.
*This research was conducted in conjunction with scientists from the 'Groupe de recherche sur la gestion des écosystèmes' of Antwerp University (Belgium) and the Centre Interniversitaire de Recherche sur le Saumon atlantique (CIRSA) of Laval University (Canada)

Freshwater Fish Invasions The Result Of Human Activity

2008-09-30T09:08:00.000-07:00

ScienceDaily (Feb. 9, 2008) — Globally, invasive species represent a major threat to native species. A new paper* shows that, for rivers and lakes, where these invasions occur is predicted by human activity; find an area where economic activity is high and, in nearby lakes and rivers, up to a quarter of species will be migrants to the region.
In the first global analysis of invasions in aquatic habitats, Fabien Leprieur, Olivier Beauchard, and colleagues investigate what factors can predict invasion events and find that human activity is to blame.
Prior to this work, ecologists have debated the relative importance of human activity and intrinsic features of an ecosystem when trying to explain the distribution of invasive species. Researchers have suggested that the number of native species would predict the number of invasive species settling in an area.
This is because either an environment that is good for fish generally, and therefore hosts lots of natives, would be good for invaders too; or, conversely, because an environment that was host to many natives would be"full" to hopeful migrants.
Leprieur and colleagues from France, Belgium, and Canada investigated the fish species found in over 1000 river basins and found that the number of native species does not correlate with the number of invasive species.
Instead, they found that invasion was related to gross domestic product, with higher human population density, and with nearby urbanized land. This raises serious concerns for the future of many aquatic ecosystems as the rate of global economic expansion continues to rise, predicting an increase in invasive species and, with it, an increase in the extinction of native animals.
*Citation: Leprieur F, Beauchard O, Blanchet S, Oberdorff T, Brosse S (2008) Fish invasions in the world's river systems: When natural processes are blurred by human activities. PLoS Biol 6(2): e28. doi:10.1371/journal.pbio.0060028

LAKE MALAWI FIELD TRIP

2008-08-14T16:34:00.000-07:00

Just come back from Lake Malawi field trip, with a lot of Cynotilapia afra collections.

The populations from Ngara to Cape Maclear, all is being tested for reproductive isolation,

hybridization and genetic diversity.

This will keep me busy until, July 09.

Watch this space for early results of my findings and impact on fish diversity,

within Lake Malawi.

A picture is Otter Point boulder, a usual dwelling place for our favourite mbuna cichlids.

Hastings

Evolution Of New Species Slows Down As Number Of Competitors Increases

2008-03-25T11:01:00.000-07:00

ScienceDaily (Mar. 25, 2008) — The rate at which new species are formed in a group of closely related animals decreases as the total number of different species in that group goes up, according to new research.

The research team believes these findings suggest that new species appear less and less as the number of species in a region approaches the maximum number that it can support.

In order for new species to thrive, they need to evolve to occupy their own niche in the ecosystem, relying on certain foods and habitats for survival that are sufficiently different from those of other closely related species.

Competition between closely related species for food and habitat becomes more intense the more species there are, and researchers believe this could be the reason for the drop-off in the appearance of new species over time.

Dr. Albert Phillimore, from Imperial College London's NERC Centre for Population Biology, lead author on the paper, explains: "The number of niches in any given region is finite, and our research supports the idea that the rate of speciation slows down as the number of niches begins to run out.

"In essence, it seems like increased competition between species could place limits on the number of species that evolve."

The new study used detailed analysis of the family trees, or phylogenies, of 45 different bird families. By examining the rate at which new species have arisen in each of these trees over a period of millions of years, scientists saw that the rate of appearance of new species seemed to be much higher in the early stages of the family tree, compared to more recent lower rates.
For example, when the researchers examined the phylogeny of tit birds they found that some 10 million years ago, species formed rapidly but this rate has slowed over time to perhaps a quarter of the initial rate.

Journal reference: Phillimore AB, Price TD (2008) Density-dependent cladogenesis in birds. PLoS Biol 6(3): e71. doi:10.1371/journal.pbio.0060071

Study Suggests Humans Can Speed Evolution

2008-03-25T10:54:00.000-07:00

ScienceDaily (Aug. 5, 2004) — Atlanta (August 4,2004) -- It’s no secret that life in the 21st century moves at a rapid pace. Human inventions such as the Internet, mobile phones and fiber optic cable have increased the speed of communication, making it possible for someone to be virtually in two places at once. But can humans speed up the rate of one of nature’s most basic and slowest processes, evolution? A study by J. Todd Streelman, new assistant professor of biology at the Georgia Institute of Technology suggests that humans may have sped up the evolutionary clock for one species of fish.

Cichlid fish are well known to biologists for their rapid rate of evolution. While it takes many animals thousands of years to form new species, the cichlids of Africa’s Lake Malawi are estimated to have formed 1,000 new species in only 500,000 years, lightning speed in evolutionary terms. In the 1960s a fish exporter may have unwittingly set the stage for an evolutionary explosion when he introduced individuals of the species Cynotilapia afra to Mitande Point on the lake’s Thumbi West Island. As of 1983, the species hadn’t budged from Mitande Point. But when Streelman, then at the University of New Hampshire, Durham, and colleagues went to the island in 2001, they found the fish had evolved into two genetically distinct varieties in less than 20 years. The study appears in the August 13 edition of Molecular Ecology.

“This is a great example of human-induced evolution in action,” said Streelman. “It adds to a growing list of cases, including introduced salmon, flies and plants, where human disturbance has set the stage for contemporary evolution on scales we’ve not witnessed before.”

The fish have evolved into two genetically distinct and differently colored populations, one on the north side of the island, the other on the south, said Streelman. Cichlid color patterns are important in mate selection, so these distinct markings may promote the evolution of new species.

Whether or not that happens and how long it will take is a question to which Streelman is eager to find the answer. “It could be that we'll have new species in another 20 years, although this depends on a number of factors. Either way, we have a wonderful opportunity to follow the evolutionary trajectory of these populations over time. We plan to return to the island next July to do further study,” he said. “Thumbi West will be a valuable place to work for years to come.”

Choosy Females Make Colourful Males

2008-03-25T10:49:00.000-07:00

ScienceDaily (May 12, 2006) — Female fish prefer brightly coloured males because they are easier to see and are in better shape concludes Dutch researcher Martine Maan following her study of fish speciation in the East African Lakes. Environmental variation subsequently leads to differences in preference and eventually to speciation.

Evolutionary theory predicts that species can diverge if different females choose different characteristics in males. Yet females often pay attention to traits that reveal something about the quality of a male. As a result, females are likely to share the same preferences. In Lake Victoria cichlid fish, Martine Maan found a solution for this paradox: in different species, different traits reveal male quality.

She examined two closely related species, one with blue males and the other with red males. Females prefer males of the right colour, blue or red, and within those categories they choose the most brightly coloured males. They do so for good reasons: brightly coloured males from both species carry fewer parasites and are thus in better condition. Moreover, both species are adapted to different infection risks, which are associated with a difference in water depth and food choice. It is therefore in the females' interest to mate with their own males.
Red and blue light

Yet how did these differences evolve? The red species occurs in deeper water than the blue species and therefore experiences different light conditions. Behavioural experiments showed that both species have adapted to this: the red species is more sensitive to red light and the blue species is more sensitive to blue light. For females of the red species, red males are therefore more conspicuous than blue ones, and vice versa. Males of other colours are inconspicuous and unattractive, and therefore produce few offspring. Eventually only the bright red and bright blue fish remain, and two separate species can arise.

Due to the introduction of the Nile perch, deforestation and population growth, water transparency in Lake Victoria is declining. In turbid water, cichlid females are less choosy and males are less brightly coloured. This research therefore underlines the importance of measures to counteract the ongoing eutrophication of the lake.

Multiple Genes Permit Closely Related Fish Species To Mix And Match Their Color Vision

2008-03-25T10:44:00.000-07:00

ScienceDaily (Oct. 16, 2005) — Vision, like other biological attributes, is shaped by evolution through environmental pressures and demands, and even closely-related species that are in other ways very similar might respond to their particular environments by interpreting the visual world slightly differently, using photoreceptors that are attuned to particular wavelengths of light. By studying a special group of closely-related fish species inhabiting the Great Lakes of Africa, researchers have uncovered clues to understanding how the components of color vision can undergo change over a relatively short period of evolutionary time.

The work is reported by James K. Bowmaker of University College London, Karen L. Carleton of the University of New Hampshire, and their colleagues.

Cichlid fish of the East African Rift Lakes are renowned for their diversity: Owing to migrations of ancestor species out of Lake Tanganyika and into other lakes, such as Lake Malawi, it has been estimated that hundreds of new cichlid species have arisen in these lakes in the last 100,000 years. Thanks to the relatively recent colonization by these fish of different ecological niches, as well as the prominent role of nuptual coloring in the mating preferences of these species, the cichlids offer a unique opportunity to study how color vision can undergo change in rapidly evolving species. For example, because color plays a significant role in mate choice, differences in color vision could greatly influence and even drive cichlid speciation.

In the new work, the researchers performed physiological and molecular genetic analyses of color vision in cichlid fish from Lake Malawi and demonstrated that differences in color vision between closely related species arise from individual species' using different subsets of distinct visual pigments. The scientists showed that although an unexpectedly large group of these visual pigments are available to all the species, each expresses the pigments selectively, and in an individual way, resulting in differences in how the visual world is sensed.

The researchers identified a total of seven "cone" (color-sensing) visual pigments underlying color vision in these cichlids. They have measured the sensitivities of the cones to different wavelengths of light and isolated the seven genes that give rise to the pigment proteins. The seven cone types have maximum sensitivities ranging from the red end of the spectrum right through to the ultraviolet--light outside the range of human sensitivity. The researchers showed that in order to tune its color vision, each cichlid species primarily expresses three of the seven cone pigment genes encoded by their genomes.

It is not clear why such closely related cichlid species have evolved such different visual sensitivities, but the sensitivities most likely relate to such selective forces as foraging specializations and subtle differences in the underwater light environment. Evolutionary comparison of pigment genes suggests that other groups of fish may use a similar strategy for shaping their color vision.

###
The researchers included Juliet W.L. Parry, Aba Carboo, David M. Hunt, and James K. Bowmaker of University College in London, United Kingdom; Karen L. Carleton and Tyrone Spady of the University of New Hampshire, Durham, New Hampshire. This work was supported by the Leverhulme Trust and by the National Science Foundation.
Parry et al.: "Mix and match colour vision: tuning spectral sensitivity by differential opsin gene expression in Lake Malawi cichlids." Publishing in Current Biology, Vol. 15, pages 1734-1739, October 11, 2005. DOI 10.1016/j.cub.2005.08.010 www.current-biology.com

Adaptation To Parasites Drive African Fishes Along Different Evolutionary Paths

2008-03-25T10:35:00.000-07:00

Captured from :

http://www.sciencedaily.com/releases/2007/08/070815101856.htm

ScienceDaily (Aug. 16, 2007) — An international team of scientists from Canada (Université Laval), the U.K. (University of Hull, Cardiff University) and Spain (Doòana Biological Station), have discovered that a pair of closely related species of East African cichlid fishes -- a group of fish whose diversity comprising hundreds of species has puzzled evolutionary biologists for decades -- evolved divergent immune gene adaptations which might explain why they do not interbreed, despite living side by side.

The two species ( Pseudotropheus emmiltos and Pseudotropheus fainzilberi ) are found in the north western part of Lake Malawi. Until now, the only known difference between them was the color of their dorsal fin. Many researchers believe that African cichlids recognize conspecifics from these kinds of colour differences, which are thought to result from sexual selection. However, recent mate choice experiments have shown that female P. emmiltos recognize males of their own species from P. fainzilberi males based on olfactory communication rather than color.

Some of the genes known to influence mating behavior through olfaction in other vertebrate species are genes of the major histocompatibility complex (MHC). These genes code for receptor that bound molecules produced by infectious agents and present them to specialized cells of the immune system which then launch an immune attack on the microbes.

They are the most diverse genes found in vertebrate genomes and individuals of some species, including humans, are able to "smell" other individuals' variability at these genes and adjust their mate choice in order to optimize the effectiveness of their offspring's immune system. Analysis of MHC genes between P. emmiltos and P. fainzilberi revealed that the two species were genetically more different at these sites involved in contacting and presenting molecules to immune cells than at other sites of the gene's DNA sequence that do not play functional roles.
These results show that natural selection has driven the evolution of these genes in different direction between the two species. Furthermore, the researchers showed that infecting parasites found on the two species were significantly different, as predicted based on the known immune function of MHC genes. "The mechanisms having produced the hundreds of species of East African cichlid fishes in a relatively short period of time are unclear", says Jonatan Blais, the senior author of the paper. "This is one of the first genetic adaptive differences between closely related East African cichlid species identified. As such, it improves our understanding of the recent evolution of this incredibly diverse group of fish by pointing to a trait that not only diverged for adaptive reasons but may also be involved in mating behavior."

"The precise role that this divergence played in the evolution of reproductive isolation has yet to be studied", comments Louis Bernatchez, co-author of the study." But it offers an exciting new perspective in the study of African cichlids speciation. "

Citation: Blais J, Rico C, van Oosterhout C, Cable J, Turner GF, et al (2007) MHC Adaptive Divergence between Closely Related and Sympatric African Cichlids. PLoS One 2(8): e734. doi:10.1371/journal.pone.0000734

'Bizarre' new mammal discovered

2008-02-01T01:36:00.000-08:00

DISCOVERY OR NAMING UNNAMED SPCIES??

The question above can only be answered by people who
keep on discivering things which have already been there
in millenia.

Hastings
=========

By Rebecca Morelle Science reporter, BBC News

A new species of mammal has been discovered in the mountains of Tanzania, scientists report.
The bizarre-looking creature, dubbed Rhynochocyon udzungwensis, is a type of giant elephant shrew, or sengi.

The cat-sized animal, which is reported in the Journal of Zoology, looks like a cross between a miniature antelope and a small ant eater.
It has a grey face, a long, flexible snout, a bulky, amber body, a jet-black rump and it stands on spindly legs.

"This is one of the most exciting discoveries of my career," said Galen Rathbun, from the California Academy of Sciences, who helped to confirm the animal was new to science along with an international team of colleagues.

They are so bizarre-looking and a lot of their behavioural ecology is so unique and interesting, you kind of get wrapped up with them

Galen Rathbun
Despite its name, the creature, along with the 15 other known species of elephant shrew, is not actually related to shrews.
Dr Rathbun told the BBC News website: "Elephant shrews are only found in Africa. They were originally described as shrews because they superficially resembled shrews in Europe and in America."

In fact, the creature is more closely related to a group of African mammals, which include elephants, sea cows, aardvarks and hyraxes, having shared a common ancestor with them about 100 million years ago.

"This is why they are also known as sengis," explained Dr Rathbun.
The new species was first caught on film in 2005 in Ndundulu Forest in Tanzania's Udzungwa Mountains by a camera trap set by Francesco Rovero, from the Trento Museum of Natural Sciences in Italy.

Dr Rathbun said: "I got these images, and said to myself: 'Boy, these look strange'. But you can't describe something new based just on photographs, so in March 2006, we went back in and collected some specimens."

Flashy creatures
He told the BBC that it quickly became apparent that the creatures were new to science.
He said: "Elephant shrews are almost all distinguished by distinctive colour patterns, and this is especially true of the forest-dwelling giant sengis.

The animal uses its long snout for scooping up insects
"They are all quite flashy - one species has a bright golden rump, another checkers along the rump - so when you have a colour pattern that just isn't similar to what is out there, you know it is fairly obvious that you have got something new.

"And this one, with its grey face and black rump, was pretty different."
As well as its distinctive colouring, the new species was also larger than other species of giant elephant shrew, weighing 700g (25oz) and measuring about 30cm (12in) in length.
It uses its long, flexible nose and tongue to flick up insects, such as termites, and it is most active either at dawn, dusk, or during the day.

Dr Rathbun added: "They are behaviourally fairly simple - they are not like a dog or cat you can interact with - but they are so bizarre-looking and a lot of their behavioural ecology is so unique and interesting, you kind of get wrapped up with them."

The scientists say there is still much to learn about the Rhynochocyon udzungwensis, but they hope further research will help to answer questions about how many of the animals exist, their range and how closely the animals live together.

Tanzania's Udzungwa Mountains are rich in biodiversity, in addition to this new species, a number of other new species have been found there, including the Udzungwa partridge, the Phillips' Congo shrew, and a new genus of monkey known as Kipunji as well as several reptiles and amphibians.

Dr Rathbun said it was vital the area and its inhabitants in this "biodiversity hotspot" were protected.

HUMAN EVOLUTION IS SPEEDING UP

2008-01-22T13:03:00.000-08:00

Hi

Hard facts to take them head on.

hastings
========

Human evolution is speeding up

Taken from BBC NEWS

By Anna-Marie Lever Science and nature reporter, BBC News

Humans have moved into the evolutionary fast lane and are becoming increasingly different, a genetic study suggests.

In the past 5,000 years, genetic change has occurred at a rate roughly 100 times higher than any other period, say scientists in the US.

This is in contrast with the widely-held belief that recent human evolution has halted.
The research has been published in the Proceedings of the National Academy of Sciences (PNAS).

Professor Henry Harpending, an author of the study from the University of Utah, Salt Lake City, US, said: "The dogma has been these [differences] are cultural fluctuations, but almost any temperament trait you look at is under strong genetic influences.

"Genes are evolving fast in Europe, Asia and Africa, but almost all of these are unique to their continent of origin," he added. "We are getting less alike, not merging into a single, mixed humanity."

This is happening, he said, because "there has not been much flow" between different regions since modern humans left Africa to colonise the rest of the world. And there is no evidence that it is slowing down, he added.

"The technology can't detect anything beyond about 2,000 years ago, but we see no sign of [human evolution] slowing down. So I would suspect it is continuing," he told BBC News.

New gene selection

Researchers found evidence of recent selection in 7% of all human genes, including lighter skin and blue eyes in northern Europe and partial resistance to diseases, such as malaria, among some African populations.

At the moment we are in an evolutionary interval. We are in between two storms
Professor Steve Jones, geneticist

"Five thousand years is such a small sliver of time," said co-author Professor John Hawks of the University of Wisconsin, Madison. "It's 100 or 200 generations ago. That's how long since some of these genes originated, and today they are in 30% or 40% of people because they've had such an advantage."

The researchers propose that there are two factors causing human evolution to speed up.
"One of them is there are a lot more people - the more people you have the more opportunities there are for an advantageous mutation to show up," said Professor Harpending.

A large population has more genetic variation and allows for more positive selection than a small one.

"The second is environmental change - our diets have changed, we are in radically new environments," he added. "With a large population size comes lots of new diseases."
Happening now?

However, geneticist Professor Steve Jones of University College London said suggesting a large population size could increase the speed of evolution was "a contentious issue".

Seven percent of human genes are undergoing rapid evolution

"Once a population gets above a very small size it is not very clear if its ability to respond to natural selection depends on size," he told BBC News.

"The general picture that evolution has speeded up in the last 10,000 years as we change from, to put it bluntly, being animals to being humans is clearly true," he explained. "To suggest it is happening at this instant, I would suggest, is probably wrong."

He said natural selection needed difference - either in the ability to stay alive or in the number of offspring born.

"The fundamental observation is that this difference has gone," said Professor Jones.
"At the moment we are in an evolutionary interval. We are in between two storms. One storm has more or less blown itself out, the storm of farming.

"The question is whether we are going to stay in the calms or whether another great storm will start. And if there is one, I would say it is most certainly to do with epidemic disease."

How they did it

The study looked specifically at genetic variations called "single nucleotide polymorphisms," or SNPs. These are single-point mutations, or changes, in the genetic sequence of DNA on chromosomes.

If the mutation is advantageous then it will spread rapidly in the population, along with DNA on either side of the mutation.

The authors argued that if the same chromosome from numerous people had a segment with an identical pattern of SNPs this would indicate that the segment of the chromosome had not been broken up (recombined) recently.

TATA NANO TECHNOLOGY

2008-01-19T14:45:00.000-08:00

Thanks to Dr Gwynne Dyer

It takes a man to put down the sentiments in your article
and you are proving to be one of the best brains on our
planet earth.

You set in a good novel thesis alltogether of what it takes
to reduce the carbon emmissions.

Hastings
=========

Nano Hypocrisy

By Gwynne Dyer

http://www.gwynnedy er.net/articles/ Gwynne%20Dyer% 20article_ %20%20Tehran% 20Times.txt

The jokes about the Nano, Tata Motors' new affordable car for theIndian middle class, were harmless, although very old. They told the samejokes about the Fiat 500 and the Citroen 2CV in the 1950s, when mass carownership first came to Europe. "How do you double the value of a Nano?""Fill the tank." "How many engineers does it take to make a Nano?" "Two.One to fold and one to apply the glue." But the hypocrisy wasn't funny atall.

The typical story in the Western media began by marvelling thatTata has managed to build a car that will sell for only 100,000 rupees (US$2,500). Everybody agrees that it's "cute", and it will take five peopleprovided they don't all inhale at the same time. It has no radio, no airconditioning, and only one big windshield wiper, but such economies meanthat it really is within reach of tens of millions of Indians who couldonly afford a scooter up to now. And that is where the hypocrisy kicked in.

What will become of us when all those Indians start driving aroundin cars? There's over a billion of them, and the world just can't take anymore emissions. It's not the "People's Car," as Tata bills it, but ratherthe "People's Polluter," moaned Canada's National Post. "A few dozenmillion new cars pumping out pollution in a state of semi-permanentgridlock is hardly what the Kyoto Protocol had in mind."

But hang on a minute. Aren't there more than a dozen million carsin Canada already, even though it only has one-thirtieth of India'spopulation? Aren't they on average twice the size of the Nano (or, in thecase of the larger SUV's, five times the size)? Does the phrase "doublestandard" come to mind?

"India's vehicles spewed 219 million tonnes of carbon dioxide intothe atmosphere in 2005," fretted The Guardian in London. "Experts say thatfigure will jump almost sevenfold to 1,470 million tonnes by 2035 if cartravel remains unchecked." And the Washington Post wrote: "If millions ofIndians and Chinese get to have their own cars, the planet is doomed.Suddenly, the cute little Nano starts to look a lot less winning." Butpractically every family in the United States and Britain already has itsown car (or two).

Don't they realise how ugly it sounds? Don't they understand thateverybody on the planet has an equal right to own a car, if they can affordit? If the total number of people who can afford cars exceeds the numberof cars that the planet can tolerate, then we will just have to work out arationing system that everybody finds fair, or live with the consequencesof exceeding the limits.

"Contraction and convergence" is the phrase they need to learn. Itwas coined almost twenty years ago by South African-born activist AubreyMeyer, founder of the Global Commons Institute, and it is still the onlyplausible way that we might get global agreement on curbing greenhouse gasemissions worldwide.

The notion is simply that we must agree on a figure for totalglobal emissions that cannot be exceeded, rather as we set fishing quotasin order to preserve fish stocks. Then we divide that amount by six and ahalf billion (the total population of the planet), and that gives us theper capita emission limit for everyone on Earth.

Of course, some people (in the developed countries, mostly) arecurrently emitting ten or twenty times as much as other people (mainly inthe developing countries), but eventually that will have to stop. The bigemitters will gradually have to "contract" their per capita emissions,while the poor countries may continue to grow theirs, until at an agreeddate some decades in the future the two groups "converge" at the same levelof per capita emissions. And that level, by prior agreement, will be lowenough that global emissions remain below the danger point.

If you don't like that idea, then you can go with the alternative:a free-for-all world in which everybody moves towards the level of percapita emissions that now prevails in the developed countries. Nonegotiations or treaties required: it will happen of its own accord. Sowill runaway climate change, with average global temperatures as much as 6degrees C (10 degrees F) higher by the end of the century. That means afuture of famine, war and mass death.

Clucking disapprovingly about mass car ownership in India or Chinamisses the point entirely. At the moment there are only eleven privatecars for every thousand Indians. There are 477 cars for every thousandAmericans. By mid-century, there will have to be the same number of carsper thousand people for both Indians and Americans -- and that number willhave to be a lot lower than 477, unless somebody comes up with cars thatemit no greenhouse gases at all. Otherwise, everybody loses.

____________ _________ _________ ________

To shorten to 725 words, omit paragraphs 3 and 4. ("What will...mind? ") Gwynne Dyer is a London-based independent journalist whose articlesare published in 45 countries.

2008 greetings to all

2008-01-07T05:22:00.000-08:00

Hi

2008 is here, I will be bring more scientific news in biotechnology,
field this year.

wishing you all the best of 2008.

hastings

“Noah’s flood” spread farming, researchers say

2007-11-21T11:55:00.000-08:00

I find the issue interesting how scientists can link the flood and agriculture.
I should say this link may also be there, why do we have a lot of
biodiversity in the tropical areas where they fall into the belt of this
flood as well. Is the Noah's issue also not connected with conservation
of biodiversity when they keep all animals male and female into
the craft??

Read On and do not shoot the messenger, but thought provoking ehh.

Hastings
===========

Nov. 19, 2007World Science staff

http://www.world-science.net/othernews/071119_flood.htm

A giant prehistoric flood—which a controversial theory has linked to the Biblical story of Noah’s Ark—kick-started European agriculture, according to a new study.A decade-old theory holds that about 7,500 years ago, a deluge filled the Black Sea in the Middle East, inspiring the Noah’s Ark flood tale and possibly some of the other flood stories that mysteriously recur in many mythologies.

Although some researchers dispute the theory, the new study’s authors take it further and say the disaster also triggered a boom in agriculture. “A catastrophic rise in global sea level led to the flooding of the Black Sea and drove dramatic social change across Europe,” the scientists said in an announcement of their findings.

The deluge “could have led to the displacement of 145,000 people,” they explained. “Archaeological evidence shows that communities in southeast Europe were already practising early farming techniques and pottery production before the Flood. With the catastrophic rise in water levels it appears they moved west, taking their culture into areas inhabited by hunter-gatherer communities” across Europe.The research, by the Universities of Exeter, U.K. and Wollongong, Australia, appears in the September issue of the research journal Quaternary Science Reviews.The trigger for the hypothesized flood would have been the collapse of the North American Ice Sheet some 8,000 years ago, according to the scientists.

This would have raised sea levels—causing water to violently breach the Bosporus Strait, which previously dammed the Mediterranean and kept the Black Sea as a freshwater lake.The Australian and U.K. researchers created reconstructions of the Mediterranean and Black Sea shoreline before and after the hypothesized sea level rise.

They estimated that nearly 73,000 square km of land, an area about the size of Ireland, was lost to the sea in one 34-year period.Controversy has dogged the flood hypothesis from the start, although it has support from evidence including signs of human habitation found well beneath the sea. One team has proposed that although there was a flood, it happened too gradually to threaten anyone, and thus cannot explain the deluge myths.

Another scientist has claimed that the true source of these tales is the presence of marine fossils in mountains: the fossils get there by geologic process, but ancient people might have seen them as proof of past floods.The authors of the Quaternary Science Reviews paper are sticking close to the original deluge hypothesis, proposed by marine geologists William Ryan and Walter Pitman in 1996. “People living in what is now southeast Europe must have felt as though the whole world had flooded.

This could well have been the origin of the Noah’s Ark story,” said the University of Exeter’s Chris Turney, lead author of the new paper. “Entire coastal communities must have been displaced, forcing people to migrate in their thousands. As these agricultural communities moved west, they would have taken farming with them across Europe. It was a revolutionary time.”* * *

HOW CAN WE TALK OF LAKE MALAWI BIODIVERSITY WHEN THE WORLD IS BURNING

2007-11-19T12:19:00.000-08:00

The world report explicitly said it all, we need to work hard to conserve the biodiversity through our reduction of green house gases. As environmental scientists lets formulate our research questions to help policy makers, come out with informed decisions on whats to need be done to save this burning planet from green house gases.

Lead on the report:
=============================

Scientists paint dire picture of hotter life on Earth

Final U.N. report more alarming than predecessors

By ELISABETH ROSENTHALTHE NEW YORK TIMES

VALENCIA, Spain -- In its final and most powerful report, a U.N. panel of scientists describes the mounting risks of climate change in language that is more specific and forceful than its previous assessments, according to scientists here.
Synthesizing data from its three previous reports, the U.N. Intergovernmental Panel on Climate Change for the first time specifically points out what is risked if governments fail to respond: melting ice sheets that could lead to a rapid rise in sea levels and the extinction of large numbers of species brought about by even moderate amounts of warming, on the order of 1 to 3 degrees.
The report carries heightened significance because it is the last word from the climate panel before world leaders meet in Bali, Indonesia, in December to begin to discuss a global climate change treaty that will replace the Kyoto Protocol, which expires in 2012. It is also the first report from the panel since it shared the Nobel Peace Prize with Al Gore in October -- an honor that many scientists here said emboldened the panelists to stand more forcefully behind their positions.
"This document goes further than any of the previous efforts," said Hans Verolme, director of the World Wildlife Fund's Global Climate Change Program. "The pressure has been palpable -- people know they are delivering a document that will be cited for years to come and will define policy."
The previous three sections, released between February and April, focused on one issue at a time: the first on science, the second on how the world could adapt to warming, the third about how countries could "mitigate," or reduce, the greenhouse gases produced.
This fourth and final assessment -- the so-called synthesis report -- seeks to combine lessons from all three. Its conclusions are culled from data contained in the thousands of pages that were essentially technical supplements to the panel's previous publications. How that data is summarized and presented to the world will be a powerful guide to what the scientists consider of utmost importance at the end of a five-year process, offering concrete guidelines for policymakers.
"You look to a synthesis report to provide clarity, to clarify what was obscure in previous reports," said Michael Oppenheimer, a climate scientist at Princeton University. "Now, how can we take these findings and formulate a policy response that's quick enough and big enough?"
Even though the synthesis report is more alarming than its predecessors, some researchers believe that it still understates the trajectory of global warming and its impact. The IPCC's scientific process, which takes five years of study and writing from start to finish, cannot take into account the very latest data on climate change or economic trends, which show much more development and energy use in China.
"The world is already at or above the worst-case scenarios in terms of emissions," said Gernot Klepper of the Kiel Institute for World Economy in Kiel, Germany. "In terms of emissions, we are moving past the most pessimistic estimates of the IPCC, and by some estimates, we are above that red line."
The panel presents several scenarios for the trajectory of emissions and climate change. In 2006, 8.4 gigatons of carbon were put into the atmosphere from fossil fuels, according to a study in the proceedings of the National Academy of Science, which was co-authored by Klepper. That is almost identical to the panel's worst-case prediction for that year.
Likewise, a recent International Energy Agency report looking at the unexpectedly rapid emissions growth in China and India estimated that if current policies are not changed, the world would warm 6 degrees by 2030, a disastrous increase far higher than the panel's estimates of 1 to 4 degrees by 2100.
While the United States, Saudi Arabia and China tried to change the text in order to downplay the consequences of global warming, developing nations -- which will bear the initial brunt of climate change -- were much more forceful than at previous meetings in opposing these efforts, according to a scientist who was in the negotiating room. "I suspect that will continue," he said.
One novel aspect of the report is a specific list of "Reasons for Concern." It includes items that are thought to be very likely outgrowths of climate change that had been mentioned in previous reports, such as an increase in extreme-weather events.
But for the first time it includes less-likely but more-alarming possibilities, such as the relatively rapid melting of polar ice. Previous reports focused more on changes the scientists felt were "highly likely."
"This time they take a step back and look at the totality," Verolme said. "Saying it is less likely to occur, but if it does, we are fried."
One such area is the future melting of ice sheets in Greenland and western Antarctica. In earlier reports, the panel's scientists acknowledged that their computer models were poor at such predictions, and did not reflect the rapid melting that scientists have recently observed.
If these areas melt entirely, seas would rise 40 feet, scientists said. While scientists are certain that the sheets will melt over millennia, producing elevated sea levels, there is now evidence to suggest that it could happen much faster than that, perhaps over centuries.
"In my view, that would make it not just difficult, but impossible to adapt successfully; some of my colleagues would say catastrophic," said Oppenheimer.
This final report also puts more emphasis on the ripple effect of small degrees of temperature change, some of which are already being seen, such as species extinctions and loss of biodiversity.
"A relatively modest degree of warming -- 1 to 3 degrees -- spells a lot of trouble, and I think that was not clear in the previous report," Oppenheimer said.
He said part of the reason for the lack of clarity was that governments had "messed around" with the language and structure of the report during the approval process.
This time around, the consequences of different degrees of climate change will be better laid out so that the ministers who meet in Bali in December will understand the options and the consequences of inaction. "This should light a fire under policymakers," Oppenheimer said.

NATURAL HUMAN HISTORY REVISITED

2007-11-14T04:28:00.000-08:00

Hi Guys

As scientists keep on looking for more evidence of evolution in human
history, one breaking moment brings them back to africa, yes the
great east africa rift valley of which Malawi is well positioned as
the epicenter of human evolution.

However, the dates are much more older than the Lake Malawi formation
dating of 1 million years ago. So may be this ape named Nakalipithecus nakayamai,
did not drink water or feed nuts irrigated from the fesh waters of Lake Malawi.
Nakalipithecus nakayamai is said to be 10 million years old.

The questions is which ape coevoluted with the maginificent lake malawi,
will be left to those who fancy the Lake Malawi cichlids and their
biodivesity, so go figure.

Hastings
================

Experts find jawbone of pre-human great ape in Kenya

By Katie Nguyen Reuters - Tuesday, November 13 03:43 pm

NAIROBI (Reuters) - Researchers unveiled a 10-million-year-old jaw bone on Tuesday they believe belonged to a new species of great ape that could be the last common ancestor of gorillas, chimpanzees and humans.

The Kenyan and Japanese team found the fragment, dating back to between 9.8 and 9.88 million years, in 2005 along with 11 teeth. The fossils were unearthed in volcanic mud flow deposits in the northern Nakali region of Kenya.

The species -- somewhere between the size of a female gorilla and a female orangutan -- may prove to be the "missing link", the key step that split the evolutionary chains of humans and other primates, Kenyan scientists said.

"Based on this particular discovery, we can comfortably say we are approaching the point at which we can pin down the so-called missing link," Frederick Manthi, senior research scientist at the National Museums of Kenya, told reporters.

"We have to find more fossils from a cross-section of sites to sustain that particular theory," he added, speaking at a desk where the approximately four-inch sliver of bone was displayed alongside human and gorilla skulls.

It was the latest important finding in east Africa's Rift Valley -- a region long regarded as the "cradle of humankind".

"The teeth were covered in thick enamel and the caps were low and voluminous, suggesting that the diet of this ape consisted of a considerable amount of hard objects, like nuts or seeds, and fruit," Yutaka Kunimatsu at Kyoto University's Primate Research Institute said in a telephone interview.

"It could be positioned before the split between gorillas, chimps and humans," he added.
However, it was hard to determine what the new species, named Nakalipithecus nakayamai, looked like.

"We only have some jaw fragments and some teeth ... but we hope to find other body parts in our future research. We plan to go back next year. We will try to find bones below the neck to tell us how the animal moved," Kunimatsu said.

Published in the latest issue of the Proceedings of the National Academy of Sciences, the finding is significant as it gives credence to the theory that the evolution from ape to man may have taken place entirely in Africa.

Prior to this finding, there had been so little fossil evidence in Africa dating between 7 to 13 million years ago that some experts began to surmise that the last common ancestor left Africa for Europe and Asia, and then returned later.

"Now, we have a good candidate in Africa. We do not need to think the common ancestor came back from Eurasia to Africa. I think it is more likely the common ancestor evolved from the apes in the Miocene in Africa," Kunimatsu said.

The Miocene is a period extending from 23.03 million to 5.33 million years ago.
"Some apes (then) left Africa and migrated to Eurasia. They then became orangutans in Southeast Asia. Today's orangutan evolved from the apes that left Africa," he said.

Technique lets scientists see brain in full color

2007-11-07T13:28:00.000-08:00

Hi Friends,

Last week it was a fast genetic mice and today its a brain colouration.

With all this fast evolving molecular technologies, why should other

people go about hungry day in day out simply becasue they missed,

the green revolution which saw the increase in food production in

the latin america and east asia.

While, I partly understand the mismatch overlooked in the food patterns

of the crops targeted in green revolution and the satple foods of sub-sahara.

These new technologies will or may equally provide the fast growing and

high yeilding crops of sub-sahara. Yes, we use our maize and cassava not

wheat and rice as promoted by the green revolution.

As a molecular biologists and concerned citizen of the underprivilaged, I

propose that scientists in this region should take the molecular techniques

seriously and think of ways how to improve the comonly used food crops,

to revolutionise the growth and productivity of these food crops.

Hastings

==========

Take note that the picture and story are credited to Nature and World science staff.

Nov. 6, 2007 Courtesy Nature and World Science staff

http://www.world-science.net/othernews/071106_braincolor.htm

With a combination of genetic tricks and fancy proteins, researchers have colored hundreds of individual cells in a mouse brain with distinctive hues. This provides a key step towards understanding how the nervous system works, both normally and in diseased brains, scientists said.

The research, published in the Oct. 31 issue of the research journal Nature, takes brain mapping to a new level, and results in the labelling of nerve cells with approximately 90 different colour combinations.

Over a hundred years ago, the Spanish physician Ramon Y Cajal opened the gates to modern neuroscience with a technique that colors nerve cells so their structure is clearly visible, called Golgi staining.

But it uses only one color, and until now it has remained difficult to map out individual cells in each brain circuit. In the new research, Jeff Lichtman of Harvard University in Massachusetts and colleagues developed a technicolor version of Golgi staining, called “Brainbow,” that they said allows more detailed reconstructions of brain circuits

Species extinctions still rising, experts warn

2007-10-13T09:28:00.000-07:00

‘Red List’ grows to 16,306 animals and plants seen as threatened

The full Red List database is online at iucnredlist.org.

MSNBC staff and news service reports
Updated: 10:50 a.m. ET Sept. 12, 2007

Nearly 200 animals and plants have been added to a global database of threatened species, the World Conservation Union announced Wednesday, adding that the number is certainly on the low end.

From the lowland gorillas of Africa to corals of the Galapagos Islands, more than 16,300 species are threatened with extinction, the group said in releasing its annual Red List.
"The rate of biodiversity loss is increasing, and we need to act now to significantly reduce it and stave off this global extinction crisis," Julia Marton-Lefèvre, the group's director general, said in a statement.

The group noted that while extinctions are a part of nature, its findings show that humans are accelerating some extinctions. "Estimates vary greatly, but current extinction rates are at least 100-1,000 times higher than natural background rates," it said in a statement.
In what is billed as the world’s most authoritative assessment of Earth’s plants and animals, the group considered 41,415 species and found that of those, 16,306 were under threat, said Craig Hilton-Tailor, the list’s manager.

That is 188 more species than last year. Even so, Hilton-Tailor said, there are probably many more than that.
'Tip of the iceberg'“The estimate is low; we know it’s low,” he said. “We’ve only really looked at the tip of the iceberg in terms of species that are out there that are known to science.”
The total number of extinWhile it does not play a major role in U.S. decisions on wildlife conservation because the United States does this through its own Endangered Species Act, the IUCN is highly influential in other regions, particularly in developing countries that cannot afford to make their own assessments of which species are in trouble.
Its members includes nations, government agencies, non-governmental organizations and thousands of scientists.

The IUCN noted that while the total number of species on the planet is unknown, estimates vary between 10 million and 100 million — with 15 million species being the most widely accepted figure. Nearly 1.8 million species are known to exist.
Corals and warming seasFor the first time, corals were added to the list due to threats that include the warm-water Pacific Ocean pattern El Nino and global warming.
"The fact that corals are now present on the IUCN's Red List should sound warning bells to the world that the oceans are in trouble," said Simon Cripps, director of the global marine program at the World Wildlife Fund, an IUCN partner.

Hilton-Tailor said global warming is a factor in these and other species’ endangerment, but not the only factor.ct species has reached 785 and a further 65 are only found in captivity or in cultivation, the group, also known by the acronym IUCN, said in its statement.
One in four mammals, one in eight birds, one third of all amphibians and 70 percent of the world’s assessed plants on the 2007 Red List are in jeopardy, the IUCN added

“It’s really hard to identify whether it’s climate change or not that’s driving some of these species to extinction,” he said. “Climate change doesn’t operate by itself, it’s operating in tandem with other threats and it’s usually the combination of climate change and possibly the threat of a new disease ... it’s different combinations that can push species over the brink.”

The Galapagos Islands saw 10 native coral added to the list, as well as 74 seaweed species.
Besides being affected by warmer water, the seaweeds are also indirectly affected by overfishing, which removes predators from the food chain and results in an increase of sea urchins and otherEbola wiping out gorillasAsked to name a particularly troubling example of an endangered species, Hilton-Tailor mentioned the western lowland gorilla, which moves from endangered to critically endangered on the latest list. Its decline is due to the Ebola virus and commercial hunting of so-called bush meat.

"In the last 10 years, Ebola is the single largest killer of apes. Poaching is a close second," said Peter Walsh, a member of IUCN's primate specialist group. "Ebola is knocking down populations to a level where they won't bounce back. The rate of decline is dizzying. If it continues, we'll lose them in 10-12 years."

Female gorillas only start reproducing at the age of 9 or 10 and only have one baby about every five years. Walsh said even in ideal conditions, it would take the gorillas decades to bounce back.
Hilton-Tailor said the plight of gorillas points up the need for better viral controls, and for an alternative source of food for people in the gorilla’s range, from Angola to Congo to Gabon. herbivores that overgraze seaweed beds.

Development is the culprit in the decline of the Yangtze River dolphin, also known as the baiji, Hilton-Tailor said. It is critically endangered and possibly extinct, with perhaps one or two individual creatures remaining in China.
Changes in river flows due to dams, pollution, over-fishing and the use of electric shocks to fish in the Yangtze system are all factors in the cetacean’s disappearance. Heavy river traffic in fast-developing China is another cause.
“Any poor dolphin would really have to do amazing acrobatics to avoid being hit by one of those ships,” Hilton-Tailor said.

Birds in declineFor birds, the Red List shows 1,221 species are considered threatened with extinction, and 189 species are listed as critically endangered. The overall status of the world’s birds has deteriorated steadily since 1988, when they were first comprehensively assessed.
Birds did see the only success story on this year's list, however. The Mauritius echo parakeet, which was one of the world’s rarest parrots 15 years ago, went from critically endangered to endangered — the only species to see its status improve.
The IUCN tied the improvement to close monitoring of nesting sites and supplementary feeding combined with a captive breeding and release program.

But it also expressed frustration that only one species on the list showed improvement.
"This is really worrying in light of government commitments around the world, such as the 2010 target to slow down the rate of biodiversity loss," said Jean-Christophe Vié, deputy chief of the IUCN’s species program. "Clearly, this shows that much more needs to be done."
The IUCN said that humans "are the main reason for most species’ decline" given their impact on habitat, introducing invasive species, unsustainable harvesting, pollution and disease. "Climate change is increasingly recognized as a serious threat, which can magnify these dangers," it said.

The group also noted that:

Most threatened birds, mammals and amphibians are on the tropical continents — the regions whose forests are thought to hold most of Earth’s terrestrial and freshwater species.
Of the countries assessed, Australia, Brazil, China and Mexico hold "particularly large numbers of threatened species."
The vast majority of extinctions since 1500 AD have taken place on islands, but over the last 20 years extinctions on continents have become as common as island extinctions.
Jane Smart, head of the IUCN’s species Program, added that protecting wildlife is in the interest of humans. "Our lives are inextricably linked with biodiversity," she said, "and ultimately its protection is essential for our very survival."

The full Red List database is online at iucnredlist.org.

Stem cell team wins 2007 Nobel for medicine

2007-10-08T04:51:00.000-07:00

STOCKHOLM (Reuters) - Stem cell researchers Mario Capecchi, Martin Evans and Oliver Smithies won the 2007 Nobel prize for medicine or physiology for their work on gene changes in mice using embryonic cells, Sweden's Karolinska Institute said on Monday.

The prestigious 10 million Swedish crown (755,000 pound) prize recognised the international team's work, saying the benefits to mankind would increase in many years to come.

Capecchi was born in Italy and is a U.S. citizen. Both Evans and Smithies are British-born. Evans is a Briton while Smithies is a U.S. citizen.

The prize awarders said the discoveries made by the three have led to a new branch of medicine known as gene targeting.

This enables certain genes to be turned off "allowing scientists to establish the roles of individual genes in health and disease".

Almost every aspect of mammal physiology can be studied by gene targeting, the institute said.
Capecchi's research uncovered the role of the genes involved in organ development in mammals and has shed light on the causes of several human birth abnormalities.

Evans's work has helped in studying cystic fibrosis and in testing the effects of gene therapy. Smithies also worked on gene targeting for cystic fibrosis and the blood disease thalassemia as well as hypertension and atherosclerosis.

"In summary, gene targeting in mice has pervaded all fields of biomedicine," Karolinska said in a statement.

"Its impact on the understanding of gene function and its benefits to mankind will continue to increase over many years to come."

Medicine is traditionally the first of the Nobels awarded each year. The prizes for achievement in science, literature and peace bearing the name of Alfred Nobel were first awarded in 1901 according to the will of the Swedish dynamite millionaire.

Catching Fish Evolving

2007-10-05T16:47:00.000-07:00

2 August 2004 article taken from

http://hcgs.unh.edu/News/ScienceNOW.pdf on 6 oct 2007

The myriad of colorful cichlid fishes of the African Great Lakes is a classic example of
explosive evolution, with thousands of species having appeared in the geological
equivalent of a blink of an eye.

Now, in a paper in this month's issue of, biologists report a close-up look at one spark in that burst of evolution. Molecular Ecology Lake Malawi, shared by Malawi, Mozambique, and Tanzania, is home to at least 500 species of cichlids, all of which probably took less than a million years to evolve from a common ancestor. Still, evolutionary biologist J. Todd Streelman of
the University of New Hampshire, Durham, and his colleagues were not prepared for the speed of evolution they discovered at the lake's Thumbi West Island.

Here, at a 100-meter-long promontory called Mitande Point, a fish dealer in the 1960s
released , a species restricted to the other end of Lake Malawi. Twenty years later, the fish hadn't ventured beyond Mitande Point. But in 2001, when the team dipped nets into the water at six spots along the island's 5-km-long coastline, the scientists found that it had spread everywhere. At each station, they netted some 40 individuals and recorded the color pattern for each.

They also took a so-called microsatellite DNA fingerprint. Cynotilapia afra As it turned out, had evolved into two distinct varieties in less than 20 years. The ones along the northern coast of the island had developed about four vertical blue bars on the black dorsal fin, whereas the ones along the southern coast had only two or C. afra has split in two in just 20 years. Amazing powers of evolution.

(The original stock had no blue bars on the dorsal fin.) Also, DNA fingerprints of fish from the north coast sites were significantly different from those of fish in the south, making it likely that the two are well on their way toward becoming separate species. Fish evolution this hasty has been recorded so far only in salmon and sticklebacks. "We were not expecting [this]," Streelman says.

Evolutionary ecologist Jacques van Alphen of Leiden University in the Netherlands is
amazed at the speed with which has split in two. "It's a very nice finding," he
says. But he hopes the researchers will continue their work to find out what is different
about the two sides of the island to have caused the two forms to evolve.

--MENNO SCHILTHUIZEN

WANTED GREENER FISH

2007-10-04T16:45:00.000-07:00

Wanted: greener fish

This news coming from the FAO chief are a welcome development, look at efforts the market is doing in order to save the remaining fishery resources.

The FAO State of Fisheries and Aquaculture Report 2006, clearly said that capture stocks have reached their ceiling and aqua production is increasing.

However it does not require a rocket scientist to understand that the aqua stocks will require capture bycatches as their feed stock ingredients, yes the much required 60 % protein source.

SO WHERE DO WE GO FROM HERE?

Ecosystem management approach .

Hastings

=======

Market trends require stronger environmental performance by seafood industry
25 September 2007, Rome - The US$400 billion seafood industry has no choice but to adapt to intensifying demand from retailers and consumers for "environmentally friendly" fish, FAO said today.During opening remarks made to industry representatives attending the 2007 Seafood Industry Congress (25-27 September, Dublin), Grimur Valdimarsson, Director of FAO's Fishing Industries Division, said that the need for seafood producers to guarantee environmental performance is unavoidable."

The push towards sustainable fisheries is not just coming from government or environmental groups, but from the market itself," Valdimarsson said, noting that major seafood retailers like Unilever, Tesco, Walmart and Asda have already committed to putting on their shelves only fish that was harvested or raised sustainably."

In recent years the seafood industry has been uncertain as to whether these trends represent a momentary fad. Today, there's no question: it's real, it's a sea change, and it's the way of the future," he said.In broad terms, this means that producers will need to be able to assure retailers and consumers that their fish were not taken from overexploited stocks, farmed in ponds where mangroves once stood, or caught in nets without turtle-saving excluder devices installed.

Doing so requires monitoring fishing activities via tracking systems, labels and similar mechanisms. There are already a number of initiatives under way that seek to do this, established either by seafood retailers or public interest organizations.

While expressing concern over the proliferation of diverse and competing efforts, Valdimarsson stressed that, overall, the trend is a positive one.Transition anything but easy"Complying with these new imperatives is technically extremely difficult, and so the challenge facing industry right now is finding ways of doing so that are both adequate and economically feasible," Valdimarsson acknowledged.

The capture fisheries sector should draw lessons from the last 25 years of food safety assurance in other sectors, which moved largely from being a government-run activity to one managed by industry itself within a government-established framework and subject to spot verification.Seafood producers have been wresting with a similar problem for years now, which could help."

Already, producers have put into place internal systems to ensure that they are providing seafood that is fresh, safe to eat, and of the highest quality -- which is what today's consumers demand," Valdimarsson said. "You don't need to invent a new agency to guarantee that environmental standards are being met -- monitor for environmental performance in a similar way, as you do for safety and quality."

Developing countries will have a tough timeResource-strapped developing countries will have a particularly hard time making the transition to fully certifying their fisheries."They've already been struggling mightily to comply with health and safety regulations on fish imports put into place by importing countries in the developed world," Valdimarsson explained.

Helping resolve this problem is an issue of particular importance to FAO, he said, adding that the retailers shaping market trends have a responsibility to help suppliers in the developing world cope.And FAO and other international development organizations working on fisheries and aquaculture will need new resources to help the developing world's fisheries sector adapt.Fishing rights keyThe widespread practice of granting open or nearly-open access to fishing grounds is another challenge."

Under the open access regime, fishing is an extremely competitive, zero sum game: if a fishermen doesn't land a fish, his competitor will, leaving little incentive to conserve the resource" according to Valdimarsson, and the consequence is overfishing. "So fishermen have a vested interest in not revealing what they've been doing.""T

hat must change, because the emerging paradigm requires the industry to be able to say exactly where, when and how a fish was caught. Only fishermen who hold clear rights and are not obliged to outfish a large group of competitors will feel secure enough to operate with that level of transparency."

Safety and quality issuesThis year's World Seafood Congress was co-organized by FAO, the United Nations Industrial Development Organization, the World Health Organization, the International Food Quality Certification Group, and Ireland's Sea Fisheries Protection Authority in collaboration with the International Association of Fish Inspectors and with the support of the Irish Sea Fisheries Board, Enterprise Ireland, and the Food Safety Authority of Ireland.

The congress has traditionally focused on seafood safety and quality issues, but environmental concerns have risen higher on its agenda in recent years.One of the most serious difficulties faced by fish exporters is coping with different safety standards being imposed by various importing countries. The need for greater harmonization of standards and more equivalence agreements, as well as the proliferation of private standards and certification schemes for fish products will also be discussed in Dublin.

Contact:George KourousMedia Relations,
FAO george.kourous@fao.org
(+39) 06 570 53168(+39) 348 141 6802

Women divers better than men – it’s official

2007-10-01T05:24:00.000-07:00

Do we have any regulatons on divers and lake malawi bodiversity protection. Yes we do not have coral reefs to destroy, BUT what about the bowers or nest of cichlids in the sandy shores habitants? AND do I hear ou well, OR someone is saying what about the slimy algae on the rocky habitants YES that food for the colourful mbuna??

HASTINGS UNDER WATER L. MALAWI

Makes me think some policy issue here between all stake holders, Fisheries Dept and Parks Dept, YES include tourism DEPT as well.

Should we say only women should be diving in Lake Malawi??

hastings

==============

SOURCE: University of Hull website

Yes your are right thats me underwater Lake Malawi

http://www.flickr.com/photos/10130807@N07/sets/72157602021139930/

Increased diving activity means that environmental damage is becoming more of a problem, but research done by the Scarborough Campus at the University of Hull suggests that men are more to blame than women Recreational scuba-diving is increasing in popularity, with holidays to exotic locations providing the perfect opportunity to explore life underwater.

The experience can be enjoyed for as little as £200, bringing money into areas where it is badly needed. The down side is that divers cause damage to reefs by accidentally breaking off bits of coral when they are swimming over it – ironic when the very thing that attracts divers to the reef is their beauty and the fish that congregate around them.

Diver damage occurs due to a lack of buoyancy control, which causes sediment disturbance, covering the reef and suffocating it. But how do divers achieve good buoyancy control?

According to Mandy Shackleton, a Masters student from the University’s Centre for Environmental and Marine Sciences, relaxation and a good breathing technique are key to maintaining control and minimising damage. Mandy has spent the last three years in Kenya, where she observed 500 divers and measured their impacts on coral reefs.

Mandy, a qualified dive master, created an underwater tick sheet to assess the different types of damage caused by male and female divers. Mandy says, “When men go diving, they experience ‘sensation seeking’.

This triggers a chain reaction of hormones: the first to be released is the stress hormone cortisol, then testosterone – the hormone linked with aggression – and finally, adrenalin. The combination of these three results in erratic, dangerous diving. By contrast, female divers have better orientation underwater: they have a greater awareness of what is going on around them, they are more conscious of safety and therefore dive with greater care.”

Dr Magnus Johnson, Head of the Centre of Environmental and Marine Sciences says, “Mandy’s research is particularly interesting because above water, men are usually cited as having better spatial awareness than women. It is perhaps a good job that men don’t have to parallel park or change lanes underwater. They would lose their no clams bonus!”

Malawi awarded on climate change

2007-09-29T09:29:00.000-07:00

This story can not go without comments from people who are so concerned with the strategies we are putting in place as Malawians on climate change. The recognition by the world body on steps taken by our counry on climate change just shows how committed as Malawians both government and individuals we are to fight this war on climate change.

It is not true to say tha Malawi does not cotribute to green house gases, but its only affected by the developed countries. As log as we are building dual carriage Masauko Chipembere Highways, then we are in the same wagon of producing green house gas by our cars traveling on those roads, let alone the high taste of 4 X 4 s by our cooporate and elite society.

I recommend the government for tracking the disposed of HCFCs refrigerators and giving a figure of remaining 15 % to deal with the problem. This just shows we are in control.

Read on the good news..

Hastings
==========

Read the story as reported BY CHARLES MPAKA 11:39:06 on 29 September 2007.

The Montreal Protocol, an international treaty designed to protect the ozone layer by phasing out of ozone depleting substances, has awarded Malawi for its strides in controlling the concentration of the gases in the country. Minister of Lands and Natural Resources Khumbo Chirwa announced this Thursday in an interview.Chirwa, who had just returned from a conference on climate change in Montreal, Canada, said the meeting recognised Malawi, alongside Nigeria and Mauritius, for its efforts in reducing levels of hydrochlorofluorocarbons (HCFCs), methyl bromide and other substances.

HCFCs, which are used in refrigerators and air conditioners, are said to be 10,000 times more potent to greenhouse effect than carbon dioxide, and therefore contribute immensely to global warming. According to Chirwa, Malawi Revenue Authority (MRA) has played a part in checking levels of the substance in the country through inspection of refrigerators and related equipment being smuggled into the country.

The minister said Malawi had so far reduced about 85 percent of the levels of the substances. The Montreal Protocol previously suggested complete phase out of HCFCs by 2030 but according to Chirwa, the deadline was not realistic considering large volumes of the substances being used in industrialised countries. “On our part, we still have to fight off the remaining 15 percent.

We are getting there but we need to accelerate our efforts. Various stakeholders have worked together for this achievement but we need to involve communities more,” Chirwa said. In 2006, Malawi developed the National Adaptation Programme of Action (Napa), a plan intended to identify priority activities that respond to her urgent and immediate needs with regard to adaptation to climate change.

The plan highlights the need to involve rural communities in vulnerable areas of the country. Sam Kamoto, Programme Manager for Wildlife and Environmental Society of Malawi (Wesm) said Malawi was being heavily impacted upon by greenhouse gases from industrialised countries, despite itself not contributing towards global warming.

The environmentalist said a coordinated and enhanced participation of local communities and civil society would help a great deal in tackling issues of climate change. Malawi was the first country in the world to phase out methyl bromide, another ozone depleting substance, in 2004.

The Montreal Protocol had recommended the phase out of the substance in developing countries by 2015. Malawi was then the second largest user of the chemical after Zimbabwe because of the tobacco industry, a major forex earner for both countries.

Crocs Found to Swim Up to 24 Miles Daily

2007-09-26T04:32:00.000-07:00

ANDREA THOMPSON

FROM: LIVE SCINCE DOT COM

Known for their lethargy, crocodiles weren't suspected to be top long-distance travelers, but a new study shows that they can cover up to 24 miles a day and find their way home from enormous distances.

To test crocodile swimming skills, researchers relocated three crocs between 32 and 80 miles (52 and 130 kilometers) away from their homes just north of Queensland, a state in the northwest of Australia, and set them free to see how well they could find their way back.

The study technique was largely put into practice by the efforts of the late Steve Irwin. Specially-designed transmitters attached to the back of the reptiles' heads allowed scientists to monitor progress, with some astounding results: the crocs swam between 6 and 24 (10 and 39 kilometers) a day, much farther than scientists previously thought they could.

One crocodile even swam around the northern tip of the Cape York Peninsula (which juts northward out from Queensland toward Papua New Guinea) to reach home, covering more than about 250 miles (400 kilometers) in 20 days.

"We often thought crocodiles tired very quickly, but here we show very clearly that they are capable of moving long distances for days on end," said study leader Craig Franklin of the University of Queensland.

Franklin says that the crocs, like birds, probably use many factors to navigate, including the position of the sun, magnetic fields, sight and smell.

"Crocodiles are more closely related to birds than they are any other reptile, so they are possibly using navigation systems similar to birds," Franklin said.

The data from the satellite tracking study, detailed in the online journal PLoS ONE, show that estuarine crocodiles are capable of moving phenomenal distances over prolonged periods of time in the ocean.

Study: Wrong fish used to save species

2007-09-06T05:23:00.000-07:00

By JUDITH KOHLER, Associated Press Writer Wed Sep 5, 9:12 PM ET

DENVER - A 20-year government effort to restore the population of an endangered native trout in Colorado has made little progress because biologists have been stocking some of the waterways with the wrong fish, a new study says.

Advances in genetic testing helped biologist discover the error, which was called a potential black eye, but they said there is still hope for restoring the greenback cutthroat trout.
The three-year study, led by University of Colorado researchers and published online in Molecular Ecology on Aug. 28, said that five of the nine populations believed to be descendants of the endangered trout were actually the more common Colorado River cutthroat trout, which look similar.

The study said the results imply that the effort has "failed to improve the species' status."
Lead author, Jessica Metcalf, who recently completed her doctorate in ecology and evolutionary biology at the university, was optimistic about the ongoing restoration program because four populations have been identified as "pure greenback cutthroat trout."
Bruce Rosenlund of the U.S. Fish and Wildlife Service, which is leading the recovery effort, said the agency is reviewing the study.

"The report is just a continuation of different expert input provided to the team for consideration for restoration," Rosenlund said.

Colorado and federal biologists have a goal of 20 self-sustaining populations of at least 500 fish each. The cost of the program was not available.

Greenback cutthroat trout were historically found in the drainages of the Arkansas and South Platte rivers in Colorado and a small part of Wyoming. They were declared extinct in 1937 because of overfishing, pollution from mines and competition from nonnative fish.

Researchers said remnant populations were found in the 1950s in tributaries and provided brood stock for fish raised in federal and state hatcheries and released in their native habitat.
The fish was added to the federal endangered species list in 1978.

The greenback were believed to be in 142 miles of waterways, including in Rocky Mountain National Park, Rosenlund said.
The new study, based DNA test results, found the greenback cutthroat trout's range is only 11 miles of streams.
The research results are a setback but state biologists believe the program will succeed over the long term, said Tyler Baskfield, Colorado Division of Wildlife spokesman.
"We've been moving fish around in the state since the late 1800s, and now the new science comes in and all of a sudden it's a different playing field," Baskfield said.
University of Colorado professor Andrew Martin, the study's principal investigator, said that while the findings might give the recovery program a "black eye," the hope is that biologists and agencies will move ahead on recovering the species before it goes extinct

Sun is not to blame for global warming

2007-07-11T14:28:00.000-07:00

My interest has always been on the impact of global warming on Zambezi and rovuma catchment areas. What will global warming contribute towards the water levels and fauna of these catchment.

These catchment are amongts the concetrated with worlds diversity, and one school of thought is that the evolution of fishes in these catchment has been contributed by the different water levels several thousand s of years being low and high at some point. This has led to emergence and divergence of fish species, presently ranking high among the colour polymorphism and hence preference from the aquarium traders.

How Will the impending excess or scartity of water affect the species diversity of this african rift valley??? ........

Hastings Zidana
=====================

AFP - Wednesday, July 11 10:25 am
PARIS (AFP) - Scientists on Wednesday said that the rise in global temperatures that has been detected over the past two decades cannot be blamed on the Sun, a theory espoused by climate-change sceptics.

British and Swiss researchers looked at data for radiation from the Sun, levels of which can cool or warm our planet's atmosphere.

They factored in a cycle which solar radiation goes through peaks and troughs of activity over a period of about 11 years.

Writing in Proceedings of the Royal Society A, a journal of Britain's de-facto academy of sciences, the team said that the Sun had been less active since 1985, even though global temperatures have continued to rise.

"Over the past 20 years, all the trends in the Sun that could have had an influence on the Earth's climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures," they write.

The study is co-authored by Mike Lockwood of Britain's Rutherford Appleton Laboratory and Claus Froehlich of the World Radiation Centre in Switzerland.

The overwhelming consensus among scientists is that human activity is to blame for the rise in global temperatures. In its latest report, issued this year, the UN's Intergovernmental Panel on Climate Change (IPCC) said that this warming is already affecting the climate system.

Since 1900, the mean global atmospheric temperature has risen by 0.8 C (1.44 F), and the sea level by 10-20 centimetres (four to eight inches).

Levels of carbon dioxide (CO2), the main greenhouse gas, have risen by around a third since the Industrial Revolution and are now at their highest in 650,000 years. Eleven of the past 12 years rank among the dozen warmest years on record.

In the past few years, glaciers and snow and ice cover have fallen back sharply in alpine regions, the edges of the Greenland icesheet and on the Antarctic peninsula have shrunk, Arctic summer sea ice has thinned and retreated and Siberian and Canadian permafrost have shown signs of thaw and fallback.

GLOBAL WARMING IS REAL

2007-05-12T12:23:00.000-07:00

Fellow Biodiversity lovers

As we can see from the artcle below it clearly shows THAT GLOBAL WARIMNG IS REAL.

my questin has been and is always "What is our role as Malawians ?" Do the parliamentarians take this issue with a priority?.

The image clearly shows that Malawi is in the band of "Areas at most risk". Let us act now by putting in place necessary policy issues like-irrigation for all crop fields by the year 2030 or 2040, thats 10 yeras before the real thing is on our neck. We can do it there are several organisation dealing with global warimng and environment where, we can tap the resources let alone the credit income which they have just been written off by our creditors. As a country we can put that money to good use other than politicking by suggesting mitigation moves of glaobal warming.

Do not say I did not warn you, have a good reading below.

Hastings

=================

Drying up and flooding out
May 10th 2007 NAIROBI From The Economist print editionRich countries may be largely to blame for adding climate change to Africa's litany of problems, but the continent's own politicians have yet to take it seriously
AT A recent African Union summit, Uganda's combustible president, Yoweri Museveni, declared climate change an act of aggression by the rich world against the poor one—and demanded compensation. The moral arguments on climate change are even murkier than arguments about other wrongs done to Africa, such as slavery, but Mr Museveni may have hit on something. If the predictions of the UN's Intergovernmental Panel on Climate Change (IPCC), hold true, climate change may have a graver effect on Africa than on any other continent; the final part of the panel's latest report has just been published (see article). Scientists now blame industrialisation (read, the rich world) for some of the warming. In any event, the contrast between poverty in Africa and carbon gluttony elsewhere is sharp. Why should the poorest die for the continued excesses of the richest?
The IPCC's most recent regional report certainly raises the spectre of rising mortality. It predicts a minimum 2.5°C increase in temperature in Africa by 2030; drylands bordering the deserts may get drier, wetlands bordering the rainforests may get wetter (see map). The panel suggests the supply of food in Africa will be “severely compromised” by climate change, with crop yields in danger of collapsing in some countries.
In the drylands, water may become a critical issue. Soaring temperatures and erratic rainfall may dry up surface water. Between 75m and 250m Africans, out of the 800m or so now living in sub-Saharan Africa, may be short of water. The soil will hold less moisture, bore-holes will become contaminated, and women and girls will have to walk ever greater distances to fetch water. Vegetative cover will recede. The IPCC guesses that 600,000 square kilometres (232,000 square miles) of cultivable land may be ruined.
Warming may also hurt animal habitats and biodiversity. More algae in freshwater lakes will hit fishing. The glaciers of Uganda's Rwenzori mountains, of Tanzania's Kilimanjaro and of Kenya's eponymous mountain may disappear; only seven of the 18 glaciers recorded on Mount Kenya in 1900 still remain. At the same time, a likely rise in sea levels may threaten the coastal infrastructure of northern Egypt, the Gambia, the Gulf of Guinea and Senegal.
There are two caveats to this gloomy scenario. The first is that some parts of Africa may benefit from climate change. Increased rainfall in highland areas in eastern Africa could, for example, be beneficial. Second, though climate-change models have improved, they have been unreliable in Africa. The broad outline is plain but the detail is guesswork.
Still, some scientists think that climate change may be even crueller to parts of Africa than the IPCC predicts. The important point, they say, is not the degree of warming but the continent's vulnerability to it. A University of Pretoria study estimates that Africa might lose $25 billion in crop failure due to rising temperatures and another $4 billion from less rain. The already impoverished drylands would suffer most. Some cite the war in Sudan's Darfur region as proof of the damage done by climate change, soil erosion and overpopulation.
Unfortunately, few African leaders have grasped the scale of the challenge posed by climate change. Most oil-producers have squandered their bonanza. Nigeria has failed to plan for how to stem the dreadful pollution in its oil-producing Delta region or to prevent desertification tearing at the fabric of its dry Muslim north. South Africa is only just beginning to own up to its coal addiction. Uganda's Mr Museveni is fighting off a rare insurrection from his supporters against plans to turn a piece of Ugandan rainforest over to farming. The World Meteorological Organisation says that weather-data collection in Africa has recently got worse, just as the need for accurate figures has grown; many of the automatic weather stations it helped set up have fallen into disrepair. The African Union has done little to sound the climate-change alarm.
Kenya's president, Mwai Kibaki, says that Africa should “join hands” with its friends in the rich world over climate change. He wants more carbon-trading projects to come to Africa; so far, most have gone to Asia. His advisers admit that Mr Kibaki's ambitious plan to turn Kenya into an industrial country by 2020 worries environmentalists, but say that reforestation, thermal power and better management of water and grazing would, if they materialised, offset the damage.
Africa emits far less carbon than other continents, so its recently faster-growing economies do not gravely menace its environment. Some rich-country consumers, however, want to punish African countries for airfreighting northwards some of their produce, from flowers to wine.
Hardier new varieties of staple crops, drip irrigation schemes and technologies such as solar power should help Africa adapt to climate change. But so can simple shifts in policy. For instance, a government decision in Burkina Faso to let farmers own the trees on their land has increased the country's tree cover.
Most vital of all is the cash—probably from rich countries—to pay for roads, schools, clinics and improvements in livestock management in the most vulnerable regions. Whether Mr Museveni's outrage will sway donors is unclear. As the G8 rich countries are failing so far to fulfil the promises they made in 2005 to boost aid to Africa, the continent should not expect much new money to protect the environment. In the short run, Africa's own politicians need to take a lead, even if the people most culpable for the damage done by climate change live elsewhere.

FISH INTRODUCTIONS WITHIN LAKE MALAWI

2007-03-30T14:12:00.000-07:00

The introduction of exotic fish species to areas where they do not naturally belong is a global problem. Apart from cases of exotic species, there are also many more cases of species transplant within the same watershed, this is the issue which mainly affects most of African and indeed Malawian water ecosystems.

What is of great concern to ecologists, enviromentalists, biologists and genetists alike is what happens next after an introduction has occurred. Mainly a concern is whether a fish species which has been introduced to a new ecosystem is going to establish itself in that new environment.

The law of nature dictates "survival of the fittest", this is equally true with the new introduced fish species to any ecosystem, whether it is a lake, river, reservoir or pond. The new species needs to have an added advantage over the native species in order to do well in the new habitant. If the ecosystem is already diverse enough and strong the new species has problems to deal with its survival. In most areas in the wolrd, aquatic ecosystems have been tampered enough so that their structures are no longer strong to resist the establishment of new species in their territories. This has been due to high human population in most shorelines, which have impacted these ecosystems to the extent of affecting their assemblages.

Lake Malawi is one of those ecosystems which has suffered human impacts due to increasing settlements and farming activities near or in the shore line. This has affected the breeding grounds of many fish species including, the most totted Lake Malawi Tilapia commonly known as 'Chambo". As if this is not enough, the Lake Malawi ecosystem is also at the moment suffering from fish transfers or what ecologists call it fish translocations. This is happening mostly with the most colourful species which are commonly known as "Mbuna". The high demand of the Malawian Mbuna to European and Asian markets has led fishermen to capture these tiny spcies as far as the northern waters and send them to the southern waters where they are freighted to outside markets. It is during these processes that some of the Mbuna species are dropped on the way and hence found to be where they do not belong.

At the moment it is not yet known whether these small species will be able to establish themselves in the new ecosystems. But the questions which we should aks ourselves as Malawians are: why do we have so many fish species coexisting in lake malawi? what mechanisms are these species using to coexists? why different fish colours in different geographic areas within the lake? what will be the response of the native species?

As one way of trying to answer these questions, I have put forward a proposal which is being funded by British Council. Anyone willing to help or collaborate in this venture just contact me using my email.

Fish behaviour and light

2007-01-08T08:51:00.000-08:00

LIGHT AND BAHAVIOUR
Light, both direct and indirect, is of great importance in the lives of fishes. In the majority of fishes, the visual organs play a substantial role in orientation during swimming, towards prey, predators, other individuals of the same species in a school, or immobile objects.

The behaviour of fish, particularly their diurnal activity and many other aspects of their life, are significantlyrelated to the degree of illumination (Kikolsky 1963). Light exerts a definite influence on a fish's metabolism, maturation, behaviour and colouration.

LIGHT WAVELENGTHS AND FISH COLOURATION
Light conditions in water differ from those on land not only in their intensity but also in the depth of penetration of the various wavelengths. The longer wavelengths (i.e. red, orange) are absorbed first, with over 25% of red light being absorbed in the first metreof water. Violet, on the other hand, becomes indistinguishable below a depth of 100 m or more (Nikolsky 1963).

Since a high percentage of red light is filtered out in the first few metres of water, bright red fishes are common. Fishes that are solid red in colour aregenerally either nocturnal or live at moderate depths (Chech andMoyle 1982).

In both situations, red light is virtually absent and ared fish tends to fade into the background rather easily. However,many shallow water fish also have red spots or lines. It is thought that such colouration is important in recognition and/or breeding; red colours would be highly visible over short distances but is difficult to see over large lateral distances (water absorbs the red)(Chech and Moyle 1982).

The visual spectrum of fish depends on the nature of their habitat; fish which live in predominantly shallow waters are more sensitive to the longer wavelengths of light (red) while, as depth increases, the visual spectrum narrows considerably, starting with the longer wavelengths (Nikolsky 1963). The majority of fish can distinguish colours quite well although the maximum distance they can see is apparently not greater than 15 metres (Nikolsky 1963).

FISH ADAPTATION TO LIGHT
Fish have a number of adaptations to varying light levels. The rodsin the retina of the eye are specially adapted for sensing in weaklight. During periods of bright illumination (i.e. daylight), the rods become buried in between pigment cells lining the retina. In contrast, the cones which are adapted to sensing brighter light, move to the surface in response to higher illumination (Nikolsky 1963). The lower part of the retina, in the majority of fish, possesses more cones, and fewer rods, than the upper surface. This is due to the fact that the upper part of the eye receives more dispersed light than thelower half of the eye (Nikolsky 1963).

A rather obvious adaptation to low light levels in a relative increase in the size of eye. This affords a much greater area for light detection. A fish with large eyes is always a give away that it should be kept in a tank with either low light levels or caves and overhangs (i.e. Squirrel fish[Holocentridae] and Cardinal Fish [Apogonidae]).

LIGHT EFFECTS ON FISH BREEDING
Light also has profound effects upon the internal mechanisms of fish. For example, light exerts a great influence on the maturationof fish as well as their development and metabolism. For a number of fishes an increase in the amount of illumination produces asignificant acceleration in the development of the egg. This often takes the form of an increase in development rate in the light and a decrease in the rate in the dark (Nikolsky 1963).

In many fish species, the maturation of the gonads depends to a large extent on the duration of light (the so called photoperiod) and its intensity. In tropical seas, where the photoperiod is not as variable as in temperate areas, the role of light is not as important and many tropical species breed year round (Nikolsky 1963).

If fish do not receive the correct amount and intensity of light, they can be severely crippled and may not develop properly. In many fish species the normal course of metabolism is disturbed if they are reared in light conditions which are abnormal for them (Nikolsky 1963).

LIGHT EFFECTS ON PREDATION
The activity patterns of most fish are also related to light.Vision-orientated predators are most active during the day, oftenwith peaks of feeding in the early morning and evening when invertebrates become more available. Piscivorous fishes are alsomost active at dawn and dusk; attracted by the feeding activities ofthe smaller fish which form their prey. At night, the day-activefish become quiescent and the nocturnal fish become active (Chech andMoyle 1982).

In this article I have pointed out some of the basic reactions of fish to light; both its duration and intensity. It can be seen that light plays a very important role in the lives of fish and this must be taken into account when keeping them in enclosed systems.

Ethanol-driven vehicle under test in Malawi

2007-01-04T02:55:00.001-08:00

conducting road tests on an ethanol-propelled vehicle.
Supporters of the project argue that a switch to ethanol fuel would not only benefit the environment but also increase employment in the country's sugarcane industry and save on foreign exchange spent on fuel imports.
According to Freeman Kalirani, a lead researcher on the project • based at Lilongwe Technical College and conducted jointly with the department of science and technology • a modified Mitsubishi Pajero will be tested over a 350 kilometre route from Lilongwe to Mzuzu.
The five-year, US$1 million project, backed by the Malawi government, is investigating the practicability of flex-fuel vehicles that use either 100 per cent locally manufactured ethanol, or a combination of ethanol and petrol.
Until February 2006, all cars in Malawi used leaded petrol blended with 20 per cent ethanol. Since then, the country has switched to unleaded petrol blended with 10 per cent ethanol. Proponents of ethanol use argue that continued over-dependence on fossil fuels has economic, social, climate and biodiversity impacts for humans and the entire ecosystem.Kendron Chisale, Malawi's deputy director of science and technology, said a switch to ethanol would allow Malawi to comply with procedures aimed at emission reduction, as agreed by parties at the 2006 United Nations Climate Change Conference in Nairobi in November. "This will eventually mitigate climate change related disasters," he says.
Charles Mtonga, an economic analyst, told SciDev.Net that one advantage of using ethanol as a renewable energy source is that it can increase employment in the sugarcane industry. "It can also save on foreign exchange lost through importation of petroleum products," he said.
But Mtonga cautioned against over-enthusiasm, calling for continued research on how vehicles previously propelled by petrol can best be modified to use ethanol.
He also warned that huge investments in production and installation of additional pumps would be required to make ethanol fuel available throughout the country.Malawi produces ethanol from sugar molasses in bulk amounts at Dwangwa, in the central region lakeshore district of Nkhota-kota.
6 times read

2007 set to be world's warmest year - Met Office

2007-01-04T02:03:00.000-08:00

LONDON (Reuters) - This year is set to be the hottest on record worldwide due to global warming and the El Nino weather phenomenon, the Meteorological Office said on Thursday.
The Met Office said the combination of factors would likely push average temperatures this year above the record set in 1998. 2006 is set to be the sixth warmest on record globally.

This new information represents another warning that climate change is happening around the world," said Met Office scientist Katie Hopkins. The world's 10 warmest years have all occurred since 1994 in a temperature record dating back a century and a half, according to the United Nations' weather agency.

The Met Office makes a global forecast every January with the University of East Anglia, and said it expected the world's average temperature to be 0.54 degrees Celsius above the 1961-1990 long-term average of 14.0 degrees.

There is a 60 percent probability that 2007 will be as warm or warmer than the current warmest year, 1998, which itself was 0.52 degrees above the long-term average it said in a statement.

Most scientists agree that temperatures will rise by between two and six degrees Celsius this century due mainly to carbon emissions from burning fossil fuels for power and transport.

They say this will cause melting at the polar ice caps, sea levels to rise and weather patterns to change bringing floods, famines and violent storms, putting millions of lives at risk.

Former World Bank chief economist Nicholas Stern said in October that urgent action on global warming was vital and that delay would multiply the cost by up to 20 times.

The Kyoto Protocol is the only global action plan to curb carbon emissions, but it expires in 2012, is rejected by the world's biggest polluter -- the United States -- and does not bind booming economies like China and India.

The Met Office said the established moderate El Nino, a phenomenon in the tropical Pacific blamed for disrupting weather patterns, would continue for the first few months of 2007.

It noted that as there was a time lag between El Nino and its full effect on surface temperatures, its influence would therefore be felt well into the year.

It will coincide with what environmentalists say will be a very busy year for climate diplomacy.

Germany, which has an active climate change agenda, has taken over the six-month rotating presidency of the European Union and the year-long presidency of the Group of Eight industrialised nations.

Backed by Britain, which has pushed climate change high up the world agenda, pressure is building for the G8 summit in Germany in early June to set out a framework for discussions to take global action beyond Kyoto

LAKE MALAWI MBUNA

2007-01-02T14:28:00.000-08:00

Mbuna is the common name for a large group of African cichlids from Lake Malawi. The name mbuna is translated as rock fish. As the name implies, mbuna are the cichilds that live among piles of rocks, as opposed to living in the open water like many other haplochromines.

These cichilds are some of the most colorful freshwater fish for the home aquarium. Mbuna, pronounced with only one syllable, are very aggressive and territorial fish, although they are suitable for beginner fishkeepers who have researched their needs. A suitable aquarium setting includes many rocks, caves and hiding places; plants may be uprooted so they are best avoided but a small number will work well in the aquarium. These include Java fern, which may become the object of mbuna aggression but will not be eaten due to an undesireable taste.

Sand or gravel is the ideal substrate. The hobbyist will want to mix in some sort of so-called "live rock" as a pH buffer. However, crushed coral and specially mixed bags of substrate will do. Generally, tanks of no less than 55 gallons are required for mature Mbuna; 29 gallon tanks will work beautifully for juvenile fish but will need to be upgraded as they mature, grow and become more aggressive and territorial (this will occur in just a matter of weeks or months).

These cichlids are usually kept in well filtered, heavily stocked mbuna-specific aquariums. Over-crowding helps spread out the aggression and no particular individual gets picked on to death. They are maternal mouthbrooders and breed readily in good conditions. Mbuna are mostly herbivorous and their diet should consist of low fat foods. Many species will require spirulina, but worms, beefheart, and meaty foods are best avoided.

There is a wide array of literature out there concerning African cichlids (including references to mbuna in more general aquarium guides and scientific texts). There are subtle but important differences from book to book (and especially from internet site to site). Differences include whether or not to attempt an under-gravel filter and specific species compatibility. Make sure that you double check any recommendations with a second or third shopkeeper, experienced aquarist or printed text. The time and monetary investment required for a 75 gallon or larger aquarium demands it.

Many mbuna cichlids are regularly stocked and sold by pet shops. Some of the most common ones are bumblebee cichlid, auratus cichlid, electric yellow cichlid, red zebra cichlid, and johanni cichlid. Cichilds belonging to any of the genera listed below is usually considered mbuna.

An electric yellow cichlid, Labidochromis caeruleus.

Labeotropheus fuelleborni
Cyathochromis Trewavas 1935
Cynotilapia Regan 1922
Genyochromis Trewavas 1935
Gephyrochromis Boulenger 1901
Iodotropheus Oliver & Loiselle 1972
Labeotropheus Ahl 1926
Labidochromis Trewavas 1935
Maylandia Meyer & Foerster 1984.
Melanochromis Trewavas, 1935
Petrotilapia Trewavas 1935
Pseudotropheus Regan 1922

The list below includes groups of non-mbuna mouthbrooding cichilds from Lake Malawi.
Peacock cichilds
Haplochromines

LAKE MALAWI FACT FILE

2007-01-02T14:16:00.000-08:00

Coordinates
10°00′S 34°00′E

Lake type
Rift Valley lakes

Primary sources
Ruhuhu

Primary outflows
Shire River

Basin countries

Mozambique Malawi Tanzania

Max-length
560 km

Max-width
75 km

Surface area
29,600 km²

Average depth
292m

Max-depth
706m

Water volume
8,400 km³

Surface elevation
500 m

Islands
Likoma Chizumulu

Settlements
Niassa, Mozambique Ruvuma, Tanzania

LAKE MALAWI WILDLIFE

2007-01-02T11:05:00.000-08:00

Lake Malawi has traditionally provided a major food source to the residents of Malawi as it is rich in fish, the most famous of which are the chambo, consisting of anyone of 4 species of the cichlid genus Nyasalapia, as well as the kampango, a large catfish (Bagrus meridionalis). Lake Malawi is famous for its cichlids, popular in the aquarium trade. Malawi cichlids are divided into two basic groups. These are loosely referred to as the haplochromines and the tilapiines. Within this first group (Haplochrominae) there are two subgroups. The first consists of the open water and sand dwelling species with males usually sporting bright colors while the females show a silvery coloration with irregular black bars or various other markings. The second subgroup is known locally and popularly as mbuna, which means rockdweller. Mbuna are smaller, generally vegetarian, and both sexes are often quite colorful, though many species are dimorphic. The second group, the tilapiines, consists of the only substrate-spawning species in the lake (Tilapia rendalli), as well as the 4 species of chambo (Nyasalapia). Maylandia and Labidochromis are popular cichlids in the international aquarium scene. Cichlids are an important export for Malawi, but wild populations are increasingly threatened by overfishing and localized pollution. Other wildlife resident in the lake includes crocodiles, and a large population of fish eagles which feed off the fish population.
The lake also supports populations of snails some of which carry bilharzia. For many years this was strenuously denied by the government, which feared it would deter tourism in the area, but since the fall of Hastings Banda, the presence of bilharzia in the lake has been more widely acknowledged. (However, due to the overfishing of snail eating cichlids in the lake, this has caused what little bilharzia did exist to greatly increase to the point of being a hazard to bathers in the south east portion of the lake.)

CICHLID HYBRID

2007-01-02T11:01:00.000-08:00

Because of the introduced nile perch and water hyacinth, deforestation causing siltation of water, and overfishing, many species of Lake Victoria cichlids have been wiped out or drastically reduced in the wild. Thankfully, the myriad of satellite lakes surrounding Lake Victoria have not been affected, and harbor a vast array of similar species.

Some cichlids have been found to hybridise with closely related species quite readily, both in the wild and under artificial conditions.[23] This is not particularly unusual, having been observed among other groups of fishes, such as European cyprinids.[24] What is unusual is the extent to which cichlid hybrids have been put to commercial use, in particular as fast-growing food fish and as aquarium fish.[25][26] A notable hybrid, known as blood parrot cichlid, has caused controversy among aquarium enthusiasts. Some has called the fish "the Frankenstein monster of the fish world." [27]

Cichlid keeping aquarists tend to divide cichlids into groups based on regions such as Central America, South America, Madagascar and India, Lake Tanganyika, Lake Malawi and Lake Victoria. Others divide the cichlids using the combination of geographical, taxonomical, and behavioral criteria. Some notable groups resulting from this type of categorizing are the mbunas, haplochromines, dwarf cichlids, and shell dwellers.
Cichlids from Lake Tanganyika were first collected by German hobbyists during the 1930's. However, it was during the 1970s and 80s that the cichlids from lakes Tanganyika and Malawi began to become popular aquarium fishes. This trend continues to the present unabated.
Perhaps the most commonly encountered species in retail aquariums is Pterophyllum scalare from the Amazon River basin in tropical South America, known in the trade as the "angelfish". Other cichlids commonly stocked by retail aquaria include:

CICHLID REPRODUCTION

2007-01-02T11:00:00.002-08:00

All species show some form of parental care for both eggs and larvae, often extended to free-swimming young until they are several weeks or months old.
The discus fish (Symphysodon species) are noted to feed their young with a secretion on the skin from slime glands. Other South American, some Central American and Madagascan cichlds have also been observed with fry feeding on their parents, but not to the extent of the discus.
Parental care falls into one of three categories: mouthbrooders, substrate brooders, and delayed mouthbrooding where the eggs are laid in the open or in a cave, and subsequently brooded in the mouth(s) of the parents. The mouthbrooding strategy for reproduction is primarily found in cichlids indiginous to the Great Rift Lakes in Africa, with South/Central American/New World cichlids tending to be substrate spawners. Mouthbrooding cichlids will generally have the female of the species immediately taking the newly fertilized eggs into her mouth where they will remain until the fry are free swimming. Some species of mouthbrooders will take food while brooding, while others will go the entire incubation period without taking any food. Most cichlids are maternal mouthbrooders, with some exhibiting bi-parental mouthbrooding, where both parents will take a turn holding the eggs in their mouth. Some mouthbrooders will release their fry once free-swimming and show no further parental care while other mouthbrooders will remain continue to guard the fry allowing them back into the mouth to escape predators. The ability to mouthbrood is thought to have been an evolutionary adaptation to reduce fry predation, likely due to the fishes being located in densely populated waters.

CICHLID DIET

2007-01-02T11:00:00.001-08:00

Cichlids are astonishingly diverse in terms of diet. Many are primarily herbivores feeding on algae (e.g. Petrochromis) and plants (e.g. Etroplus suratensis) and small animals, particularly invertebrates, are only a small part of their diet. Some cichlids are detritvores and eat all types of organic materia; among these species are the tilapias of the genera Oreochromis, Sarotherodon, and Tilapia.
Other cichlids are predatory and eat little if any plant matter. These include generalists that catch a variety of small animals including other fishes and insect larvae (e.g. Pterophyllum), as well as variety of specialists. Trematocranus is a specialised snail-eater, while Pungu maclareni feeds on sponges. A number of cichlids feed on other fish, either whole or in part. Crenicichla are stealth-predators that lunge at small fish that pass by their hiding places, while Cichla are open water pursuit predators that chase down their prey. Paedophagous cichlids such as Caprichromis species eat other species' eggs or young (in some cases ramming the heads of mouthbrooding species to force them to disgorge their young). Among the more unusual predators are Plecodus straeleni feeds on scales and fins ripped from other fishes, and Nimbochromis livingstonii, which lies on its side and plays dead, hoping to lure smaller fish close enough for it to snap them up.
Scientists believe it is this wide adaptability of feeding styles that has helped cichlids to inhabit such a wide range of habitats. It is largely the pharyngeal teeth (teeth in the throat) that allows the cichlid so many 'niche' feeding behaviors, i.e. the jaws may be used to hold or pick food, while the pharyngeal teeth are used to crush what was harvested.

CICHLID RANGE

2007-01-02T10:59:00.000-08:00

Cichlids are mainly freshwater fish that are most diverse in Africa and South America, with at least 900 species in the former and 290 in the latter.[14] Substanial numbers are also found in Central America as far north as the Rio Grande in southern Texas, and Madagascar has its own distinctive fauna of cichlids phylogenetically only distantly related to those on the African mainland. [15] [16] Endemic cichlids are largely absent in Asia except for four species in the Middle East, one in Iran, and three in the Indian Subcontinent.[17] Europe, Australia, Antarctica, and most of North America do not have any native cichlids, although where environmental conditions are suitable, for example in Florida and northern Australia, feral populations of cichlids have become established as exotics. [18] [19]
Cichlids are less commonly found in brackish and salt water habitats, though many species will tolerate brackish water for extended periods; Cichlasoma urophthalmus, for example, is equally at home in freshwater marshes and mangrove swamps, and can be found living and breeding in salt water environments such as the mangrove belts around barrier islands. [20] However, only a few cichlids are found primarily in brackish or salt water, most notably Etroplus maculatus, Etroplus suratensis, and Sarotherodon melanotheron

GET TO KNOW THE CICHLID FISH

2007-01-02T10:58:00.000-08:00

Cichlids are members of a group of perciform fish known as the Labroidei alongside the wrasses Labridae, damselfish Pomacentridae, and surfperches Embiotocidae. This very large grouping shares a single key trait: the fusion of the lower pharyngeal bones into a single tooth-bearing structure. A complex set of muscles allows the upper and lower pharyngeal bones to be used as a second set of jaws for processing food, allowing a division of labour between the "true jaws" (mandibles) and the "pharyngeal jaws". Cichlids in particular have evolved to be very efficient feeders that are able to capture and process a very wide variety of food items and this is assumed to be one reason why they are so diverse (see section on diet below).[11]
The particular features of cichlids that distinguish them from the other Labroidei include:[12]
A single nostril on each side of the forehead instead of two.
No bony shelf below the orbit of the eye.
The lateral line organ is divided into two sections, one on the upper half of the flank and a second along the midline of the flank from about halfway along the body to the base of the tail (except for genera Teleogramma and Gobiocichla).
A distinctively shaped otolith.
The small intestine leaves the stomach from its left side, not from its right side as in other Labroidei.
Extensive brood care, with eggs and fry being guarded by one or both parents

The ethical guide to eating fish 2

2007-01-02T10:04:00.000-08:00

***** Eat at will. **** Some stocks are endangered, so find out where your fish was caught. Bycatch not a major issue. *** Stock depletion is a problem. Often caught or reared in a way that kills other animals or harms the marine environment. ** Best avoided unless you can establish that it came from a sustainable fishery or was farmed using low-impact methods. * Sorry, this is one fish that you'll have to leave well alone.
SalmonTop facts: Migrate from spawning gravel 'redds' in upper reaches of river out to sea before returning to river of birth to spawn. Can reach a length of 1.5m and weight of 36-45kg. Status and problems: Stocks of wild Atlantic salmon have been halved in the past 20 years and are vulnerable to overfishing by driftnet fisheries and to parasites such as sealice and other impacts from salmon farms. More than 99 per cent of salmon sold in UK shops is farmed, with associated environmental impacts. For a clearer conscience: Buy organic farmed salmon, MSC-accredited fresh Alaska salmon or tinned Pacific salmon. Rating: **
Cod Top facts: Found in North Atlantic. Omnivorous and cannibalistic. Flesh is more than 18 per cent protein with virtually no fat. Status and problems: Affected by overfishing and climate change. Assessed as vulnerable on the IUCN Red List (www.redlist.org). North Sea stocks are on the brink of collapse, with 40-45 per cent of 2-8 year-old fish removed every year by fishing. Recovery plans now in place in Irish and North Seas. For a clearer conscience: Only Icelandic cod are from sustainable sources, but keep an eye on Iceland's proposal to cull whales to protect fish stocks. Pollack, coley and hoki (from MSC-accredited fishery) are alternatives. Rating: ***
Haddock Top facts: An important commercial species with a distribution similar to that of cod. Migratory fish, found in inshore, shallow North Atlantic waters in summer and in offshore deep water in winter. Reported maximum age of 20 years and a maximum size of between 0.8m and 1m (growth rates vary with sea temperature). Status and problems: Species listed as vulnerable by IUCN. Many stocks overexploited, including in the North Sea. Quotas reduced between 2000 and 2001, most notably in Irish Sea. For a clearer conscience: As with cod, Icelandic stocks are sustainably managed. Go for line-caught fish for less bycatch. Rating: ****
Prawns Top facts: Two species are popular in the UK: northern prawns, which are found on muddy sea-bottoms in cold water, and larger tiger prawns, from warm, tropical waters. Status and problems: Cold-water prawn stocks in North Sea considered within safe biological limits. Tiger prawn trawl fisheries associated with large quantities of bycatch, including turtles. Tiger prawns are also farmed, requiring large quantities of feed and causing destruction of coral reefs and mangrove swamps. Sea. For a clearer conscience: Try to find cold-water prawns that have been caught in traps rather than trawled. Avoid warm-water species. Rating: ***
Mackerel Top facts: Fast swimming species related to tuna, found in mid-water in huge schools above the continental shelf. Status and problems: Common in the North Atlantic, but large-scale purse-seine fisheries can result in bycatch of marine mammals, such as dolphins, local stock depletion and bycatch of juvenile fish. North Sea stock long since depleted. For a clearer conscience: Buy MSC-labelled fish from the South West Handline Fishery. Contact David Muirhead Tel 01326 555813 or check out the MSC website (details on main page) for certified retailers and distributors. Rating: **
Trout Top facts: Member of salmon family with similar lifecycle. There are two species, of which rainbow trout is non-indigenous introduction from the US. Native species are either sea trout (females which migrate from rivers and lakes out to sea) or brown trout (non-migratory males which stay in freshwater). Status and problems: Both species widely farmed, and being carnivores (like salmon), they require fishmeal. Non-indigenous rainbow interbreeds and competes with native species, and brown trout are threatened as a result. For a clearer conscience: Buy organic trout where you can. Rating: **For a clearer conscience: Try to find cold-water prawns that have been caught in traps rather than trawled. Avoid warm-water species. Rating: ***
Plaice Top facts: Widely distributed in temperate waters of Atlantic, Indian and Pacific Oceans. Bottom-dwelling fish found on sandy bottoms, buried in the sand during the day and active at night. Long-lived, with a reported maximum age of 30 years. Spawns between January and March after long migration.Status and problems: Beam- and bottom-trawling cause damage to seabeds. Overfishing - especially of immature fish - is threatening stocks, as the fish only matures at the age of seven, and so large fish are now rare.For a clearer conscience: Look for line-caught fish from day boats.Rating: ***
Brown crab Top facts: The largest British crab, found on the lower shore down to a water depth of about 100m, usually among rocks or under boulders. Has characteristic 'pie-crust' edge to its shell.Status and problems: Common around UK and European coasts, but many stocks are now overfished - it is estimated that more than 60 per cent of our crab populations are being harvested each year.For a clearer conscience: If you buy your crab alive, you will have to kill it yourself. The most humane method of killing a crab is to 'spike' it in its two nerve centres - behind the eyes and on the underside of the 'apron'.Rating: ***
Herring Top facts: An oily fish rich in Omega-3 acids, it is often sold smoked (as a kipper).Status and problems: Widespread species - the Guinness Book of Records lists it as the most numerous fish - though it can be overfished locally. UK stocks collapsed in 1970s, resulting in a total fishing ban. Now well managed, though industrial harvesting for fishmeal poses future threat.For a clearer conscience: Look for MSC-accredited Thames herring from spawning beds off West Mersea, in Essex. Contact Alex Midlen from the Essex Estuaries Initiative for further details Tel: 01206 282480.Rating: ****
Skate Top facts: From the same family as rays, skates are bottom-dwelling fish usually found in shallow coastal waters. Like other elasmobranchs (sharks and rays), skates are vulnerable to overfishing because they mature late. They grow to more than 1.25m and can live up to 50 years. Status and problems: Two species are exploited - common skate, which is listed as endangered by the IUCN and has probably been fished to extinction in the Irish Sea and is very rare in the central and southern North Sea, and thornback ray, which is assessed as low risk.For a clearer conscience: Avoid, unless you know it's a thornback ray.Rating: *
Sole Top facts: Dover and lemon are the two most popular sole species. Like others in its family, a sole's left eye migrates over the top of the head during growth and ends up beside the other. Status and problems: Both species are caught by beam trawls that damage the seabed. Though not endangered at present, sole are vulnerable to overfishing, particularly of immature fish. For a clearer conscience: Ask for line-caught fish from day-boats working out of small ports in Cornwall and Devon.Rating: ***
Coley [saithe]Top facts: From the same family as cod and haddock. Gregarious fish that occur in both inshore and offshore waters, living close to the seabed, and widely distributed in North Atlantic. Dark green in colour, it can grow up to 1.3m long and for 25 years. Status and problems: Species not threatened, but catches of North-Sea stock are outside safe biological limits, with many immature fish being landed. Bottom-trawling causes damage to seabeds.For a clearer conscience: Go for Norwegian and Icelandic stocks.Rating: ***
Tuna Top facts: Six commercially important species: albacore, bigeye, northern and southern bluefin, skipjack and yellowfin. Most popular tinned fish in UK.Status and problems: World catches have doubled in the past decade, and now albacore, bigeye, northern and southern bluefin are all listed by the IUCN. Bycatch of marine mammals still a problem. For a clearer conscience: Pole-and-line methods of capture are 'dolphin friendly', but may catch seabirds. Avoid scarcer species, such as bluefin, which are popular in sushi and sashimi restaurants.Rating: **
Mussels Top facts: Bivalve mollusc, normally found in large numbers, that attaches itself to the rocks and other mussels with sticky threads known as byssus. Filter-feeds on plankton. May live more than 15 years. New Zealand green-lipped mussels are imported.Status and problems: Mussels are widely cultivated, and stocks are generally considered to be well above maximum sustainable yield. Dredging causes damage to seabed.For a clearer conscience: Buy farmed rather than dredged. Mussel cultivation, like scallop farming, is extensive and low-impact.Rating: ****
Hake Top facts: Moderately deep-water fish which lives close to the bottom during day but moves into mid-water to feed at night. Very popular in the Mediterranean, particularly Spain.Status and problems: Many stocks at serious risk of collapse, in particular northern hake, which are found from Skagerrak (between Denmark and Norway) to the Bay of Biscay. Recovery plans developed by the EU in 2001 include a 74 per cent quota reduction. Bycatch of marine birds and turtles in longline fisheries also an issue.For a clearer conscience: Best avoided.Rating: *
Whiting Top facts: A slender-bodied fish, common in inshore waters, feeding on shrimps, molluscs and small fish. Grows to between 0.3m and 0.5m long. Migrates to open sea after the first year of life and is an important part of the diet of larger fish and seabirds. A good choice for those on a low-fat diet.Status and problems: Caught by bottom-trawling, which causes damage to the seabed, and is part of a complex mixed fishery (like cod), and so discards are a problem.For a clearer conscience: Ask for line-caught fish.Rating: ***
Langoustine (scampi) Top facts: 10-legged crustacean. Much smaller than the common lobster at up to 15cm in length. Lives in burrows in soft mud or sand and feeds on worms, molluscs, crustaceans and scavenged material. Often deep-fried and served as scampi.Status and problems: Widely distributed in North and Irish Seas and in waters west of Scotland. The most commercially important shellfish species in the UK. Catches are mostly inside safe biological limits, but some stocks are overfished.For a clearer conscience: Choose langoustines caught in pots or creels.Rating: *****
Halibut Top facts: Two species are exploited - Atlantic and Greenland - and both live in deep, cold waters. Atlantic halibut is larger than Greenland halibut and can attain a maximum size of 2.5m and live for up to 50 years.Status and problems: Both species vulnerable to overfishing because of their slow growth rates and late age of sexual maturity. Stocks of Atlantic halibut greatly diminished, and the species is listed as endangered by the IUCN. Bycatch of marine wildlife in both longline and gill-net fisheries.For a clearer conscience: Choose Greenland over Atlantic and hook-and-line caught fish.Rating: ***
Scallops Top facts: Bivalve molluscs which live on the seabed and are hermaphrodites (ie, both male and female). They may live for 20 years or more.Status and problems: Distributed widely throughout Atlantic waters from Norway to the Iberian Peninsula. Most common method of capture is dredging, which damages seabed.For a clearer conscience: Ensure you eat either hand-picked or farmed scallops, which are generally larger and of better quality than dredged ones. For more information, contact Jane Grant: Tel: 01445 731477; e-mail: scallops@isle-ewe.co.ukRating: **
Seabass Top facts: Spiny-finned fish closely related to groupers. Migrates to fresh water during the summer. May exceed 25 years of age.Status and problems: Though common in seas off UK, seabass is vulnerable to overfishing as the winter fishery targets spawning and pre-spawning fish. Bycatch of marine mammals in some trawls.For a clearer conscience: Avoid fish caught in winter and by pair-trawling, which is responsible for cetacean deaths in the English Channel. Farmed fish from the Mediterranean available.Rating: **
Lobster Top facts: Territorial, living in crevices or underneath rocks, coming out to feed mainly at night. Its dark blue shell turns red when boiled.Status and problems: Stocks in traditional lobster areas are now depleted, with removal rates of up to 70 per cent. For a clearer conscience: The Cornwall Sea Fisheries Committee has set up a commercial hatchery. Contact Edwin Derriman Tel: 01736 369817. Lobsters are generally boiled alive. The RSPCA advises freezing them for two hours beforehand so that they go unconscious and suffer a less painful death.Rating: **
Spiny [piked] dogfish Top facts: Member of same family as sharks and rays. Gives birth to live young after a gestation of between 18 and 22 months. Nursehound and spotted catshark also referred to as dogfish. Status and problems: Distributed throughout Atlantic, including the Mediterranean and Black seas. North Atlantic stocks have a well-documented history of overexploitation followed by near-collapse. Vulnerable to overfishing because of low reproductive capacity. Listed as near threatened by the IUCN. For a clearer conscience: Sold as rock salmon, flake or huss. Best avoided.

The ethical guide to eating fish

2007-01-02T10:03:00.000-08:00

The ethical guide to eating fish

The expression 'plenty more fish in the sea' shows how seafood has long been viewed as inexhaustible, but the reality is that fish stocks around the world are under threat. According to the UN, nearly 70 per cent of marine fisheries are either fully or overexploited and 10 per cent are depleted or recovering from depletion.

So should a conscientious consumer stop buying fish altogether or eat only those species that are not overexploited? Or choose farmed fish over wild ones?
Such questions inspired Bernadette Clarke of the Marine Conservation Society (MCS) to write the Good Fish Guide. Clarke recommends that you ask a few questions about the fish you are about to buy. For starters, find out where the fish has come from. North Sea cod is endangered but other populations off the coast of Iceland are healthy and fished sustainably.
Size does matterThe size of the fish or fillet you're buying is important. Catching small, immature fish denies them the opportunity to reproduce. You should also establish how your fish was caught. For example, dredging for scallops involves scouring the seabed with a plough-like apparatus, and the damage is akin to digging up a meadow for the odd turnip.
Diving for scallops has little impact on the environment, but is labour-intensive and unlikely ever to meet demand. Scallop farming is, however, a truly sustainable method of food production.

The problem with fish-farmingNot all aquaculture is so benign. Sealice proliferate in the densely stocked cages of salmon farms, and can infect wild fish, while escaped fish may interbreed with their wild cousins, diluting the gene pools of fish that have evolved into river-specific populations. Furthermore, salmon are fed on small, bony fish, which are being caught in ever-increasing quantities for fish farms and are the prey of beleaguered, wild fish such as cod, haddock - and salmon.

Organic salmon, certified by the Soil Association, is now widely available. At least 50 per cent of the fish-meat in the pellets fed to organic salmon must come from the by-products of wild fish caught for human consumption. The balance must be sourced from sustainable wild resources.
Sustainable fisheriesThe Marine Stewardship Council (MSC) certifies sustainable fisheries. Fish that carry the MSC logo come from healthy stocks and are caught using non-damaging techniques. Similarly, the EC has introduced a regulation ensuring traceability, and from now on all fish will have to be clearly labelled with basic information about its origins. If you need more details, ask the fishmonger or the chef. If you don't get satisfactory answers, don't buy - there are many more ethical fish you can fry.

NETWORK OF AFRICAN SCIENTISTS

2006-12-21T16:37:00.000-08:00

NETWORK OF AFRICAN SCIENTISTS

Date: 6 Dec 2005
Scientists who have emigrated from developing countries to work abroad can help address the brain drain with even short visits to their countries of origin (Hailemeskel Bisrat, 2005). Even small actions, when added together, can make major impacts on the lives of individuals and scientists in African nations.

It is a fact that an increasing number of African specialists have migrated to the north over the past three decades, while we may also agree that due to imbalances in working conditions between African laboratories and those of developed countries, many African scientists will continue to migrate abroad, however simple interventions can be made to balance the situation.
The Network of African Scientists is one of those simple interventions which aims to connect all scientists of Africa , working within the region and outside the region. The network realizes the struggles which most of the African laboratories are going through in order to access new information or materials to support their research work. The network will act as a platform of information exchange between the African scientists working abroad and those working on the African soil. We all know the power of the Internet and how it can turn tables on the good way around, if well managed for the benefit of those lacking latest information in many different fields.

In his speech the former president of South Africa Nelson Mandela said " Africa is beyond bemoaning the past for its problems. The task of undoing that past is on the shoulders of African leaders themselves, with the support of those willing to join in a continental renewal. We have a new generation of leaders who know that Africa must take responsibility for its own destiny, that Africa will uplift itself only by its own efforts in partnership with those who wish her well."
The Network of African Scientists will join all African scientists who are willing to renew the continents science through sharing of information and forming new partnerships in different fields of science. Any scientists willing to join hands in this Network should subscribe to the following site

CONSERVATION GENETICS OF LAKE MALAWI CICHLIDS

2006-12-21T15:03:00.000-08:00

Lake Malawi is believed to contain more endemic fish species than any other lake in the world and the species are estimated to be 450–600 species (Genneret al. 2004a). The rocky habitats of Lake Malawi are dominated by the mbunagroup of cichlid fish. The mbuna do not cross into other habitats like the sandy shoreline or deep waters.However as a consequence of the aquriumexport trade, some varieties of mbunahave been translocatedfrom their native localities and released at sites where they do not naturally belong e.g. since 1996, 12 varieties of mbunahave been recorded at NkhataBay that were absent from previous surveys (Genneret al., 2006).

The possible dangers of fish translocation may be competition and hybridization. It is the aim of this blogger to understand the implications of fish translocations within Lake Malawi.