Re: Why Large Gap Between Species...?

5 Dec 1996 18:59:37 GMT

Geoff Alex Cohen ( wrote:
: T&B Schmal ( wrote:
: : In article <581tr6$>, (Nat
: : Turner) wrote:
: :
: : > This has never been clear to me. Now that we've established man's
: : > origins, how do we explain the absence of all his closely related
: : > sub-species?

: : Good question. Lions, cheetahs, leopards, wolves - all survive in Africa
: : and they *don't* dedicate themselves to wiping each other out.

: Basic demographic theory would tell us that when two species compete,
: either an increased population of species 1 inhibits itself more than
: it inhibits species 2 (because of the competition), or it inhibits
: further growth of its own population more than it inhibits growth of
: the competing population (because of the carrying capacity of the
: environment).

: Two competing species can only co-exist if they both inhibit their own
: population as they grow more than they inhibit their competitor.
: This is obviously what's happening in coexisting carnivore population.

: So I theorize without evidence other than extinction of all other hominid
: (hominoid?) species that homo sapiens can outcompete other hom* species
: to the extent that an increased number of homo sapiens inhibits the
: population of competitors more than it inhibits the population of homo
: sapiens.

: The Lotka-Volterra equations describe these relationships quite elegantly.

And quite invalidly when you bother to check out real ecologies.
Ecological vicars are very common.

Harry Erwin, Internet:, Web Page:
49 year old PhD student in computational neuroscience ("how bats do it" 8)
and lecturer for CS 211 (data structures and advanced C++)