Punctuated Equilibrium

One of Stephen J Gould's major contributions to evolutionary biology was the concept of punctuated equilibrium. A short and inexact desription of this theory is that a species' genetic pool tends to remain largely unchanged with some minor slow drift over long periods of time only to significantly change relatively rapidly when the species is faced with a sudden ecosystem challenge.

The example frequently used is a long term change in rainfall leading to an altering of amphibian habitat leading to shifts in ecosystem and available resources, although new competition from another organism in the same ecological niche can produce similar results.

This theory altered the previous concept of a slow and steady arc of constant mutation, and replaced it with the idea of long periods of relative equilibrium, punctuated by more sudden evolutionary changes as new stressors are added to a system. (This "faster evolution" still takes place on a very long time frame.)

So, why am I talking about this? Polizeros had this interesting article which could indicate a very slight beginning on the process. (It is theorized that behavioral shifts usually happen far more readily than morphological shifts.)

Evidence is growing that climate change is leading to genetic changes that are passed down the generations in animals as diverse as birds, squirrels and mosquitoes, scientists report.

A wide range of animal populations has changed genetically in response to altered seasonal events and not to the expected direct effects of increased summer temperatures, according to Dr William Bradshaw and Dr Christina Holzapfel of the University of Oregon, Eugene in the journal Science.

"Over the past 40 years, animal species have been extending their ranges and populations have been migrating, developing or reproducing earlier," said Dr Bradshaw......

But that is not the whole story, said Dr Holzapfel. "Studies show that over several decades, rapid climate change has led to heritable, genetic changes in animal populations."

Now, this is one study/one researcher early in the process and I haven't looked at his data or research. Even within the concepts of punctuated equilibrium/sudden stressed evolution, this is a very short time frame, but I find it intriguing nonetheless.