From National Geographic News: Brown anole lizards on tiny islands in the Bahamas were enjoying the good life, untroubled by a lizard predator found on larger islands nearby.
But all that changed when biologist Jonathan Losos (homepage) of Harvard University in Cambridge, Massachusetts, appeared on the scene.
Losos’s team experimentally introduced predatory curly-tail lizards onto six islands where the ground-dwelling anoles had been living free of predators, sparking a see-saw year of natural selection.
For the smaller anole lizards, a trait that was advantageous in November – six months after the introduction – had become a liability by May.
…The evolutionary experiment, reported in tomorrow’s issue of the journal Science, reveals that, even though evolution can seem like a slow process, its driving force – natural selection – can shift like the wind.
The study also supports a somewhat controversial idea in biology: Animals’ behavior in response to environmental change can spur evolutionary adaptations.
Continued at “Evolution’s ‘Driving Force’ Shifts Based on Behavior, Study Says“
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Based on the Science paper “Rapid Temporal Reversal in Predator-Driven Natural Selection“
Read Jonathan Losos’ paper “Adaptation and speciation in Greater Antillean anoles” (Open Access/Free)
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See “Model of an Internal Evolutionary Mechanism” (Draft)
John Latter / Jorolat
Evolution Research:
http://evomech3.blogspot.com/
“the loss of part of a lizard population due to predation” is indeed a mechanism behind evolutionary change and commonly referred to as natural selection. Nature selects those individuals with traits that are better able to survive and only those individuals with advantageous traits will live to have offspring. And to put it simply, yes, variety within a species and a change in the gene pool are all part of the evolutionary process.
I fail to see how the loss of part of a lizard population due to predation could be a “driving force” behind evolution. There would be a loss of genetic information from the population, and the remaining population could only continue to reproduce lizards using the remaining gene information they possessed. They were not shown to form some new information or some new means of escaping the predator. There was only a “culling” out of those with the less favorable leg length. How can this be evolution? Were they becoming something other than lizards? Is variety within a kind of animal actually evolution?
Although interesting, and probably scientifically fruitful, isn’t introducing a non-native species into an isolated habitat extremely ecologically dangerous?
There are major programs underway to prevent massive extinctions in some areas due to invading species, why voluntarily court such a scenario? I am sure the researches took this into consideration, and it was not likely to resemble the problems such as zebra muscles, but why take the chance?