[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Dinosaurs versus mammals




On Fri, 23 May 1997, Jonathan R. Wagner wrote:
>         Part of my point in saying they got there "the firstest with the
> mostest" was that it may have happened so fast, and hinged upon so many
> factors (some to many of which may not have had to do with anatomy, at least
> not anatomical adaptations expressed in the fossil record) that we may not
> be able to determine it.

I agree with this.  But I think your second, more refined, answer points
out a problem with your first ("the firstest with the mostest") answer.
The correct answer is that because, as you say, this depended on so many
things we cannot determine, then we actually _don't know_ why dinosaurs
preempted their niche.  The tendency, post _Spandrels_, is to eschew
adaptationist answers altogether and say: "It was chance".  I side with
Mayr who says we should exhaust all possible adaptationist explanations
first before we accept stochastic explanations as sufficient.  I believe,
in this instance, if we actually knew the truth, the answer would include
words such as--agility, digitigrade, metabolism, bipedality, and so on,
_as well as_ words such as--exaptation, environmental filips etc.

>         While I applaud your search for answers, I hesitate to accept
> "adaptionist" answers. IMHO, they are frequently too simple and do not make
> ecological or evolutionary sense. 

Right.  But complex adaptationist answers which take ecology and evolution
into account must make more sense than facile claims of random causation.
I recently participated in a long discussion criticizing Gould's facile
stochasticist explanations with regard to the human clitoris.  His glib
claim that it is non-adaptive seems to fly in the face of his own plea for
deeper understanding by shying away from _adaptationist_ arguments.  And
on this list we have had, in my view, fruitful discussions on what
adaptations led mammals to be preeminent in some niches.  I claimed
stealthy reproduction was critical.  Others thought that teeth and
thermoregulation were more important.  I think non-scientists would be
appalled at the amount of disagreement there is about even the most basic
questions such as these.  But they prove to be amazingly complex!  I'm
trying to say that these conversations are worth having, and that they are
preferable to facile stochastic answers which don't explain and often are
simply wrong.  There is a strong burden of proof these days on
"adaptationist" explanations.  This is as it should be.  But stochastic
causation should also be scrutinized.  Too often it is not.

Finally, in answering the gentleman's question it is more scientific to
speculate adaptationist causes (as long as we state that we are
speculating) than to claim truth for facile stochastic ones.