Non-Tech: Lizards - observing evolution in laboratory time

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Non-Tech: Lizards - observing evolution in laboratory time

Postby Timothy Chase » Thu Nov 16, 2006 9:16 pm

In their criticism of evolutionary theory like to argue that evolution is limited to studying the past and as such cannot be subject to experimental testing - despite the fact that evolutionary theory often predicts exactly what sort of evidence one will later find and has been used to make a large body of predictions which were subsequently confirmed.

When it is pointed out that even the limited claim that evolution is "untestable under laboratory conditions" is false - given the study of bacteria and viruses, they then like to argue that such experiments are only being performed on micro-organisms - and that any purported instances of such evolution cannot occur within the lifetime of a given scientist. Of course, this has also been demonstrated to be wrong - with such once dramatic discoveries as whole genome duplication in orchids which we now realise is quite commonplace.

Likewise, the following story demonstrates that the claim that "one can show natural selection in action in experiments over a reasonable amount of time only with micro-organisms" is false as well. Recently, experiments have been performed over the stretch of a year confirming a hypothesis that with the introduction of predators, island lizards would first see a lengthening of their limbs (which took place over the first six months), then a shortening of their limbs as they became increasingly adapted to an arboreal environment.

Pressured by predators, lizards see rapid shift in natural selection
Public release date: 16-Nov-2006 ... 111406.php

Evolution in which behavior changes first followed by heritable morphological change is known as the Baldwin effect - wherein the heritable genetic changes begin with the filtering of naturally-occuring variation within a population and subsequent mutations may serve to stabilise a given phenotype. This sort of evolution promises to bring about evolutionary change at a considerably accelerated rate relative to evolutionary change which is originates at the genetic level simply as the result of mutation. It is becoming increasingly clear that this effect plays an important role in the evolution of animals.

The technical article will be coming out in the journal Science this week.
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Timothy Chase
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