On Wed, 7 Apr 2004 16:38:53 +0000 (UTC), Jeffrey Turner
 wrote:


>
>Let's do a nice little experiment with random drift.  Fill a box with
>marbles, half blue and half red.  Proceed to shake the box.  How long
>before the red marbles drift to one side of the box and blue marbles
>to the other?  Now, again, explain why two halves of a population with
>a non-adaptive trait "differentiating" them would separate into two
>species.
>

Let's do a better little experiment that truly encapsulates random
drift. Fill a box with marbles, half blue and half red.  Shake the box
to mix them thoroughly.  Now draw 6 marbles from the box.  Rebuild the
full population in the box from these six, in the same proportion and
check to see whether you still have half blue and half red.

Two geographically separated (allopatric) populations can accumulate
non-adaptive differences in mating behavior (cricket calling songs,
firefly flashing pattern, etc), or non-adaptive differences in details
of reproductive structures (many arthropods) or cellular recognition
factors in egg and sperm (all prezygotic species isolating mechanisms)
or else chromosomal mutations that result in hybrid breakdown or
sterility or incompatibility (all postzygotic species isolating
mechanisms).  This would result in two species.
---
þ RIMEGate(tm)/RGXPost V1.14 at BBSWORLD * Info{at}bbsworld.com

---
 * RIMEGate(tm)V10.2áÿ* RelayNet(tm) NNTP Gateway * MoonDog BBS
 * RgateImp.MoonDog.BBS at 4/8/04 6:44:40 AM