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Re: The Potentials....




On Sat, 25 Jul 1998, John M. Dollan wrote:

> In your own opinions, with perhaps a little explanation, I'd like to
> know what type of Dinosaur might have evolved into intelligence had the
> KT extinction never occured.

Probably none.  Firstly, it's arguable whether intelligence (I assume
you mean human-type intelligence, because crows, for example, are
incredibly smart in their own way) had to evolve at all.  Gould has argued
that it is just one possible evolutionary path that may or may not have
been followed.  But I don't agree with him.

But the main restriction to amassing the incredible number of neurons
required to handle the complex manipulation of symbols for language, for
example, is oviparity.  As long as embryos are developing external to the
parent's body, there is a rush to develop.  In this rush the brain is
apparently the pacemaker.  That is, it is the organ which takes the most
assembly time.  But incubation times are selected for speed by predation.
In the case of the ostrich, such a rush to be up and running probably
_causes_ its small brain size (Bertram).  Unfortunately, once the brain's
wiring is fixed for motor control, further gross development is hindered
by these permanent connections.

And let me editorialise for a second.  I would be interested to read about
a dinosaur civilization--but I don't think I could really buy into it
unless they figured out viviparity.  But this is unlikely since such a
massive evolutionary "event" as the placenta is unlikely to spring up in
non-avian size dinosaurs.  And, since their smaller members were probably
preyed to extinction by us mammals---we win!

A more interesting approach (maybe I should try it) would be a scenario
where our own super-brained species has to watch ourselves go slowly
extinct because some environmental change suddenly throws the advantage
back over to oviparity.  Well maybe this has already happened given the
diversity of ovips vs. vivips--they win!