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Archive for the ‘Science’ Category

A very ambitious and exciting project.

 

Last year, Dr. Cranston and other experts gathered at a meeting called by the National Science Foundation, where they came up with a plan for a single tree of life. On May 17, the National Science Foundation announced that it was awarding the team a three-year grant of $5.7 million.

The first goal of the project, known as the Open Tree of Life, is to publish a draft by August 2013. For their raw material, the scientists will grab tens of thousands of evolutionary trees that are archived online. They will then graft the smaller trees into a single big one.

Open Tree of Life Project Draws In Every Twig and Leaf – NYTimes.com

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An interesting study on how female guppies’ likeness for the colour orange is used by predatory shrimp to lure them close.

“This is the first significant advance on predatory lures for 100+ years and the first experiment really addressing why a lure should actually work,” John Endler, an evolutionary ecologist at Deakin University in Australia, wrote in a email. Endler, who was not involved with the research, co-authored a study in 1990 that linked female preference for orange guppies with the prevalence of orange-colored males.

That predators might have co-opted a prey species’ color preference in order to entice that prey is a “new, interesting twist” on color bias, which states that animals evolve preferences and even high visual acuity for colors relevant to their survival and reproduction, added Greg Grether, a behavioral ecologist at the University of California, Los Angeles, who was not involved in the work. Grether’s work, for example, has shown that female guppies’ love of orange pushed male guppies to maintain the right orange shade.

Read more here – How Prawns Lure Prey | The Scientist

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Deutsch: Astyanax mexicanus, Characidae, Blind...

Image via Wikipedia

 

The blind cave fish is commonly found in many shops and has been a favourite in the hobby for many years. It exists in various caves in Mexico and has long been known to be the same species as the Mexican tetra, Astyanax mexicanus found above ground. Now a new study by a team of researchers from Portugal, America, and Mexico has shed some light into how they came to be.

 

It seems that the various underground populations are more closely related to the above ground form than to other populations of blind fish. In other words the blind form has evolved multiple times. A striking example of what is known as convergent evolution. Not only that but a significant amount of cross breeding between the two forms still takes place. The fact that the blind form still persists in spite of a constant influx of genes from the sighted form is evidence for a very strong selection pressure against eyes within the environment of the caves. Blind fish are clearly able to produce more offspring in the caves than are sighted fish.

 

Read more here.

 

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How fish choose their mates

Guppies - from wikipedia

When male guppies choose females to mate with, it seems they can be quite choosy.

Males decide how much effort they put into courtship and which females to court based on how many others they have recently encountered and how attractive they were, according to a new study into the mating tactics of tropical fish.

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Some species of cichlid form groups with younger fish looking after babies. Often these fish are unrelated to the larger , more dominant fish.

Cooperative breeding of this kind has puzzled evolutionary biologists for a long time as it is costly and often does not generate obvious fitness benefits to subordinates. In the case of Neolamprologus. pulcher, the main benefit for subordinates to stay in a territory of dominant breeders seems to be the protection gained against predators provided by the large group members.

This study shows a direct relationship between the relatedness of these helper fish to the offspring and the amount of care they provide.

More here.

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With some species of cichlid fish the male takes eggs into his mouth and nurtures both them and the developing young. Up until now it’s not been certain if he was the genetic parent of the young or had been fooled into looking after them by the female.

The study, led by a research team at Kyoto University‘s Graduate School of Science, has found a solution to the mystery of whether mouthbrooding females transfer their young to any male fish in their school or specifically to their mating partners, by proving that the male fish the females shift the young to are indeed the genetic fathers of the young.

More here.

 

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Charles Darwin proposed the theory of evolutio...

Charles Darwin - Image via Wikipedia

Scientific papers can often be difficult to access without expensive subscriptions. This is especially true for non-scientists and those of us outwith academia. Well now some good news. The Royal Society Journal Archive has been made permanently free to access. This is a brilliant resource for research going back centuries and it’s now free. It includes papers by Charles Darwin, Ralf Britz, Tan Heok Hui and many others so well done to The Royal Society.

More details here.

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