From: spike66 (spike66@attbi.com)
Date: Thu Jan 16 2003 - 20:48:16 MST
Damien Broderick wrote:
> http://www.theage.com.au/articles/2003/01/16/1042520723454.html
>
> Biologists say they have found what is quite likely to be the first
> documented case of "re-evolution"...
>
> The biologists are challenging that assumption based on its analysis of DNA
> from 37 species of the insect order Phasmatodea - commonly known as "walking
> sticks" - which showed that they evolved from winged to wingless and back
> again. In fact, walking sticks made the shift four times.
>
> The discovery calls into question one of the tenets of evolutionary biology:
> that if a species loses a complex characteristic, the gene or genes that
> express it will subsequently mutate so much that the function can never be
> recovered. [etc]
Damien, the apparent puzzle is resolved from insights
provided by chaos theory. Turns out, it is very difficult
to tell what is a complex characteristic from its appearance.
A wing certainly looks complex, but the DNA required to
make an ordinary skin cell might be as complicated as
an insect wing.
Consider the cockroach. These bugs have it all. In addition
all the other breaks nature has provided, they can fly. They
seldom do so, however. I am not surprised if their evolutionary
path shows their wings coming an going periodically. spike
This archive was generated by hypermail 2.1.5 : Tue Jan 21 2003 - 17:10:21 MST