Received: by alpheratz.cpm.aca.mmu.ac.uk id UAA00669 (8.6.9/5.3[ref pg@gmsl.co.uk] for cpm.aca.mmu.ac.uk from fmb-majordomo@mmu.ac.uk); Mon, 3 Dec 2001 20:29:59 GMT Message-ID: <001101c17c39$5be997a0$11a6bed4@default> From: "Kenneth Van Oost" <Kenneth.Van.Oost@village.uunet.be> To: <memetics@mmu.ac.uk> References: <200112030529.fB35TFI19575@mail1.bigmailbox.com> Subject: Re: circular logic Date: Mon, 3 Dec 2001 21:29:20 +0100 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2314.1300 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Sender: fmb-majordomo@mmu.ac.uk Precedence: bulk Reply-To: memetics@mmu.ac.uk
>The thing is, according to Devillers and Chaline, that not only the neck,
>but
>also the frontlegs of the animals were getting longer. The result of both
>processes, forced upon them by the environment, is that the giraffe,
without
>standing up on its backlegs can now reach a hight of six meters ( 20 feet).
>All is due to habits. And the habit, more likely the need, of reaching for
>the
>highest leaves resulted in changes.
>
Nope. Shorter giraffes starved to death, taller ones (however 'taller' was
manifested, by neck or legs or both) survived to reproduce, giving us a new
spectrum of heights in succeeding generations; the shorter ones of these
generations starved to death, too, and the median giraffe height rose as a
consequence of this blind purposeless natural environmental selection of
certain mutations over others, or of one end of that species'
body-configuration spectrum over the other, in continuous iteration.
Hi Joe,
Can 't agree !
There were way back that time no shorter giraffes !
The giraffes were the adaption ! There were only bigger animals which could
reach the top leaves of the trees easily. Environmental changes forced some
of them to reach for still more higher leaves, maybe the leaves of a tree
where
they did not feed on usualy.
According to Dawkins, the shorter necks did not die out. The giraffe as we
know it today had an ancestor more likely something like the okapi.
This could be a classic example of cultural transmission via imitation.
The little ones of those animals who reached for the highest leaves did so
too. The other ones stayed behind and evolved into the okapi of today.
Cultural transmission can last for a very long time, maybe this one has been
picked up by the natural selection criteria.
IMO, 2 possibilities,
1_ the ancester of the okapi and the giraffe was a bigger animal overall,
but
with a shorter neck. In that case they could reach for the leaves on top,
for still higher leaves, they could stand on their backlegs.
Out of that one ancestor two species evolved, okapi and giraffe.
2_ the ancestor of the okapi and the giraffe was not that bigger than the
okapi we know today. In that case the giraffe evolved (A) along lines
of cultural transmission, variation and selection. Only one new species
evolved,
the giraffe. The mutual ancestor became the okapi. ( slow evolution)
(B) According to Dawkins, the change occured in one big mutation leap,
although he does not believe this himself. ( an evolution jump)
The difference between the neck of the giraffe and the one of the okapi
is very slim. The difference is that by the giraffe the vertebrae and
eveything
else were pushed out of eachother. This is streching an old existing
structure,
not the introduction of a new.
Not one starved to death, taller animals reached for the higher leaves,
the smaller animals were happy to get the ones halfway. Everybody
reproduced, but where there was once one species, two developed.
The first got six of one, the second got half of the dozen.
Regards,
Kenneth
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