Received: by alpheratz.cpm.aca.mmu.ac.uk id VAA08724 (8.6.9/5.3[ref pg@gmsl.co.uk] for cpm.aca.mmu.ac.uk from fmb-majordomo@mmu.ac.uk); Wed, 8 Aug 2001 21:11:47 +0100 Message-ID: <002b01c12046$1ab2a780$6787b2d1@teddace> From: "Dace" <edace@earthlink.net> To: <memetics@mmu.ac.uk> References: <3B708804.8677.7A8E14@localhost> Subject: Convergence Date: Wed, 8 Aug 2001 13:09:56 -0700 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Sender: fmb-majordomo@mmu.ac.uk Precedence: bulk Reply-To: memetics@mmu.ac.uk
It's well known that atavistic traits commonly pop up among developing
organisms. A feral pig is liable to develop tusks. Horses occasionally
grow extra toes. Humans are sometimes born with a small tail. Such things
can be expected if we do indeed resonate with past forms. But they can also
be explained according to the genetic model. What can't be explained
genetically is parallel evolution, or "convergence." Among plants and
animals, we continually find new examples of organisms widely separated in
their phylogenetic derivation which nonetheless develop remarkably similar
forms. In New Zealand we find many kinds of leaves common to Eurasia which
serve to fend off herbivores that don't exist in New Zealand. There seems
to be no reason why marsupials and mammals would develop such incredibly
similar forms. Why should butterflies or fish of different species in
different locations develop almost identical color patterns on their wings
or scales? In some cases animals mimic others that are poisonous to
predators and are thus avoided by predators along with the poisonous
varieties. But this explanation fails to apply in the vast majority of
cases.
Dawkins discusses this dilemma in The Blind Watchmaker: "It is vanishingly
improbable that the same evolutionary pathway should ever be followed twice.
And it would seem similarly improbable, for the same statistical reasons,
that two lines of evolution should converge on the same endpoint from
different starting points. It is all the more striking... that numerous
examples can be found in real nature, in which independent lines of
eovlution appear to have converged, from very different starting points, on
what looks very like the same end-point."
According to Sheldrake's model, organic systems resonate with similar
systems. We resonate with ourselves individually, with our species, and
with any other species which is similar enough to our own. If flying
squirrels, jerboas, and moles are all emerging in both Australia and
Eurasia, they will be drawn into similar evolutionary pathways due to their
resonance with each other. Outside of this model, there's no explanation
for convergent evolution.
Ted Dace
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