Bertvan@aol.com wrote:
>New biological systems and body parts due to parabiosis, Siamese twinning or
>integration of symbionts. While I don't full understand any of these, they
>sound like biological innovations whith the complex function already
>assembled and in working order. Why would they need "natural selection"?
>While it is true, they might all arise without ID, how DO they arise? How
>WOULD a duplicated gene turn around and suddenly start performing an
>entirely different function?
The stuff I talk about is perhaps more speculative than what you're used to.
I don't see how you can in the same breath question the possibility of
some complex structure evolving and then ask why it would need natural
selection at all, if the thing just pops into existence.
Anyway, the idea is that organisms can increase their number of parts
by increasing the number of segments. This can happen quickly; then
through slow evolution the parts are adapted to various functions.
Single-celled organisms become multicellular by duplicating themselves.
Cells gain in number of parts by integrating with organisms that were
formerly discrete symbionts. These are mechanisms for saltations.
The saltations don't suddenly spring into perfect form. It takes time
for parts to be reduced and specialized into a nice feature. But this
does explain how you can have complexes of parts that could not
logically evolve through gradual accretion, as Darwin thought.
--Cliff Lundberg ~ San Francisco ~ cliff@noe.com
This archive was generated by hypermail 2b29 : Wed Mar 29 2000 - 03:29:16 EST