Squirrels Evolving to Suit Global Warming?

Gavinsblog writes "New Scientist is reporting that using a technique called quantitive genetics, researchers have found that due to the effects of global warming, female squirrels now give birth on average 18 days earlier in the year than their great-great-grandmothers. Is global warming also affecting human evolution?
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Comments

causality or correlation?

[jo-do-cus]

What i dont get: where did they get the information that these changes are "due to global warming" ?? It's not like you can interrogate a squirrel to ask them why his genes are different.

Probably the scientists saw the correlation with the changing climate and wrote that this would be 'a possible cause for that'. Journalists normally twist the meaning and content of scientific reports to make a nice headline, eventuakky becoming "Squirrels Evolving to Suit Global Warming".

Generally, one cannot claim that species evolve for some purpose, and even if it would be so, then how do you prove that any change in genes is due to some cause??? It's all just correlations and some hopeful guesses, if you ask me.

Evolution of human?

[Gadzinka]

Is global warming also affecting human evolution?

There ain't no such thing as human evolution (anymore).

The evolution is a trials and errors process. During the duplication of DNA sometimes something goes wrong and the result isn't a perfect copy of the original.

This is called a mutation.

As a result some function of the organism is different. The change may be beneficial for the organism or it may render it handicaped. For every positive mutation there are houndreds of thousands negative mutations.

Who's to tell which mutations are positive and which are negative?

Natural selection.

If/when a particular mutation has some features that allow it to dominate gene pool it is positive. If the mutation causes premature death, sterility etc the faulty genes do not enter the gene pool. This is negative.

In order for humans to evolve we would have allow natural selection to work. We don't do this. It is not the survival of the fittest for a long time.

Robert