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November 12, 2003

No, not saltationism....

Research Sheds New Light on Process of Evolution:

For more than a century, scientists have concluded that a species evolves or adapts by going through an infinite number of small genetic changes over a long period of time.

However, a team of researchers, including a Michigan State University plant biologist, has provided some new evidence that an alternate theory is actually at work, one in which the process begins with several large mutations before settling down into a series of smaller ones.

Here is the abstract in Nature.

Posted by razib at 05:28 PM

Natural selection doesn't involve infinite small changes, it involves a finite series of changes, some small, some larger. The larger the change the less likely it is to prove beneficial, but the further it can launch a species across a valley between mountains in the fitness landscape.

These discussions always position that there is something qualitative under debate, but actually it is merely a question of degree. Some scientists feel most changes are small, resulting
in nearly continous evolution, while others feel the changes are larger, giving evolution more of a stop-and-start quality, but the underlying mechanisms and overall results are the same.


Posted by: Ole Eichhorn at November 12, 2003 07:00 PM