Re: Alex's gibbon-like CA

Paul Crowley (
Sun, 12 Nov 95 22:56:07 GMT

In article <48587j$> "Phil Nicholls" writes:

> Paul Crowley <> graced us with the following
> >There are two sorts of evolutionary change and this error confuses
> >them: (a) where the species gets split by a geographical feature or
> >environmental change and gradually drifts apart, as we see with
> >chimps, gorillas and orangs within the last 2Myr; and (b) where a
> >small group establishes a new ecological niche, for which it will
> >need a relatively short period of isolation.
> < snips >
> In (a) abov, geographical isolation will alter the geographic range of
> the species involved. Thus it is occupying a new niche.

This is nonsense. As Mark Hubey has told you before: you are
confusing habitat and niche. If the two species of chimps were put
into the same bit of forest, they would most certainly *not* occupy
different niches.

> Environmental change will also result in a new ecological niche. The
> only difference between (a) and (b) then is that you are less specific
> in (b) as to what aspects of the organisms niche is new and that the
> size of the population is initally small.

The most common occurence of (b) is when a small part of the population
start to exploit a new source of food, e.g. a group of insects start on
a new kind of plant. With a little bit of isolation that group will
evolve into the new niche and soon become a new species. This is boring.

> >Do you also agree that climatic change (especially an adverse one) is
> >unlikely to have been a factor?
> No one said anything about "adverse" changes.

The whole point of "forced" evolution is about adverse change. The
forests thin out and the quasi-gibbons had to walk more. Remember?

> It is unlikey that any major evolutionary change takes place in the
> without environmental change.

This is crazy. Where did *you* learn your evolutionary theory?
The first finches that got to the Galapagos benefitted from an environ-
mental change(EC). Were the 13(?) other speciations also the result of
EC? Are all the billions of species the result of EC? OK, you can
always go back a stage and find a change. You could always say that
they are all the result of the Big Bang. (That was some EC!) But if
you do that you are just into tautology. *Without* going back a
stage, only a very small proportion of species arise from EC.

> >BTW I keep seeing the "evolution forces" error everywhere, and it
> >drives me bananas. Today's UK Times has a report from Dr Charles
> >Goodhart of Cambridge Univ stating the some h.s.s. were "forced"
> >by climatic change to move south around 70kya. (It's only a news-
> >paper report so I may be being unfair to him - but it is typical.)
> >My point is that such change is slow in terms of a hominid lifetime.
> >No h.s.s. packed his bags and said "Brrr, it's getting cold, let's
> >go to Egypt this winter". It's a tempting scene, but it could not
> >be more wrong.
> Ahhh!!!!! Now I get it. Your a literalist! Think, Paul. 70,000
> years ago. Europe. Ice Age. What do you think Dr. Goodhart might
> have been referring to?

Assuming Dr Goodhart's words were correctly reported, what sensible
meaning could he have had? The Ice Age forced some individual
hominids to physically move south? I'm at a loss for any other
meaning. You tell me.