Re: Speciation - how do you know?

Susan S. Chin (susansf@netcom.com)
Mon, 9 Sep 1996 03:54:20 GMT

Tim Edwards and/or Marghie Parsons (tedwards@DialUp.FranceNet.fr) wrote:
: Hi.
: I spotted an article in Newsweek about a Japanese researcher who wants
: to try to fertilize a modern Indian elephant with the frozen sperm of
: a woolly mammoth. (Not anthro, I know, but bear with me). How can he
: know whether mammoth and elephant are similar enough to produce
: fertile offspring? (I suppose, if it works, he will know for sure.)

: In paleoanthropology, how do researchers determine that one creature
: is not the same species as another? Am I correct in my understanding
: that the question is still open vis-a-vis modern humans and
: Neanderthals? Is it pretty much accepted that Homo Erectus was a
: separate species?

: Tim Edwards - interested lay-person

There are actually two concepts of species here:
(pardon me while I dig thru old notes from college ... :)

The paleontological species centers around morphology, that is how
paleoanthropologists recognize one species versus another, in the absence
of interbreeding. That is how Homo erectus is distinguished from the
Neandertals and also from archaic Homo sapiens. Morphological character
differences which are thought to correlate with biological reproductive
isolation.

The biological species is defined largely on interbreeding, as well
as morphology. So how closely do paleo species approximate biological
species? Modern biological species are "defined" by breeding, but in
practice recognized thru their morphology. With this in mind, recognizing
species in the fossil record becomes less of a problem. The resolution is
not there to know about reproductive capabilities of differing fossil
species, but the degree of morphological change between two species are used
to infer that they are two distinct, reproductively isolated entities.

*** The above was taken from a paleo class a few years back, but I
think the concepts still apply. And obviously, some of the ideas were NOT
expressed in my own words***

I'm not up on the whole Neandertal/H.s.s. debate, but Homo erectus is
most certainly recognized as a separate species. There may in fact be 2
or 3 species within all the known fossils assigned to Homo erectus,
depending on the level of variability one feels can be accomodated
within one paleontological species.

Susan

-- 

                                             susansf@netcom.com