>>>Chris Cogan: ...
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DNAunion: I would like to add that the randomness/chance I was referring to
in one of my earlier posts on this topic is not based on the environment at
all.
When say 500 sea-turtle eggs hatch on the beach and the newborn make a mad
dash towards the safety of the water, birds are present and pick them off
one by one. The decision of which turtles will live and which will die is
based almost entirely on chance. There are no baby seaturtles that can
spring 100 MPH across the beach to reach the water, there are no baby
seaturtles that can overpower and kill an attacking bird, there are no baby
seaturtles that operate in stealth by blending in perfectly with the beach,
etc. It is a free-for-all with luck ruling (like when Lucille Ball is working
at a bakery on the assembly line that is running at double overdrive speed:
she can't get all of the cakes loaded into a box (or whatever) and so only
some of them make it safely while others pile up on the floor: but none of
the cakes themselves are any more fit than the others).
And even some mature animals die by chance. If a pride of lions charges a
herd of zebra, sure, the "weakest" will most of the time be the ones that are
caught: but sometimes, the smartest, strongest, and fastest zebra might
happen to be in the wrong place at the wrong time (or "trip", or run the
wrong way, or whatever) and get eaten.
In these chance deaths, the number of copies of genes that confer a selective
advantage is reduced. And any brand new advantageous alleles that these
unlucky organisms chanced to possess for the first time, but never had a
chance to pass on to any offspring, will have to arise all over again de novo
(which takes a lot of time).
This archive was generated by hypermail 2b29 : Mon Dec 04 2000 - 19:33:08 EST