Re: Where are the zoologists?

Richard Sharpe (sharpe@nmesis)
20 Dec 1994 01:26:54 GMT (Pat Dooley) writes:
: In article <3cipq6$>, (Joel Hanes) writes:
: Both anthropologists and vert. paleontologists are
: aware of the general falsity of "strict adaptionism" --
: the idea that every feature of an organism is to be
: explained, somehow, as an adaption to some selective
: pressure.
: It's my impression that many species are the way they
: are "for historical reasons" (as we say in software).
: By contrast, it seems to me that the larger scientific
: community and the popular press have yet to hear
: that evolution is contingent -- that some things just
: end up the way they do by accident, for no particular
: reason.
: ------------------------------------------------------
: Response:
: The minor features are probably random. Many feature
: hang around because they are there doing nothing. But
: major features, such as bipedalism, that required a host
: of consequential adaptations, some of which are still
: not perfect, do not arise randomly.
: In software terms, going from quadrupedalism to
: bipedalism means rewriting all the locomotion routines,
: the balance routines and the make program.

Umm, many species that we would call quadrupedal also include bipedal
locomotion in their behavioural repetoirs. For example, bears, which
walk plantigrade and are quadrupedal, also, on occassion, can move about
bipedally. Chimps, which habitually employ knuckle walking, will also
move about bipedally.

I would also venture to state that all mammals go through a learning
period, where they lean to do well the things that they must do through
out life. It is just not true that these things are inbuilt to the
degree that you imply above. Bipedalism can appear in a species that is
not fully adapted to it, and then natural selection can drive them
towards better adaptation to it.

Finally, you haven't been paying attention to Phil Nicholls comments
about suspensory feeders and bipedalism. Such species would be

: Pat Dooley

Richard Sharpe,, Ph: 61-8-235-7237, FAX: ...-7299
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