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From: jc@cdx39.UUCP (John Chambers)
Newsgroups: sci.bio
Subject: Re: The Red Queen
Message-ID: <530@cdx39.UUCP>
Date: Mon, 22-Dec-86 17:00:30 EST
Article-I.D.: cdx39.530
Posted: Mon Dec 22 17:00:30 1986
Date-Received: Tue, 23-Dec-86 21:41:06 EST
References: <741@aecom.UUCP> <925@husc6.UUCP>
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Organization: Codex Corp, a division of Motorola; Canton, MA, USA
Lines: 31
Summary: remember random mutations...

> >It has often been argued that biological change (evolution, I daresay)
> >can occur even in the absence of environmental change.  To some this has
> >been used to discredit the entire evolutionary scenario. 

Anyone that argues that environmental changes are necessary to drive
evolution is simply ignorant of the low-level mechanisms.

Consider the scenario:  A stray alpha particle comes zipping along, 
smashes through the fringes of a DNA helix, and when the electrons
settle down again, a nucleotide or two have been changed.  About 3
times out of each billion such occurrences, this is in a cell that
produces a sperm or ovum, and the change is passed on to offspring.

Furthermore, there's no problem coming up with 'constant' features
of the environment that exert selective pressures.  One such is
called 'predators'.  Even if the predators were unchanging, they 
would still select for avoidance capabilities in a prey species. 

Alpha particles and predators are part of the environment of
all living creatures.

[OK, a flying alpha particle isn't a feature of a 'constant'
environment.  But in that sense, there is no evolution in a
truly constant environment, because everything is at absolute 
zero and there is no life.]

-- 
	John M Chambers			Phone: 617/364-2000x7304
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