Re: Hominid speciation

Guy Hoelzer (
Tue, 08 Aug 1995 10:58:20 -0800

In article <402pul$>, (Phil
Nicholls) wrote:

> A species is a group of ancestor-descendent populations, not just
> populations in the here and now. In my opinion, a species may undergo
> directional change over time in terms of morphological characteristics
> but this itself is not enough to justify calling it a new species.
> For example, if we are going to maintain that a single unbranched
> lineage connects Homo habilis, Homo erectus and Homo sapiens, what is
> our justification for using three species names? If no speciation
> event has occurred then no new species has emerged.

This is an example of the common difficulty encountered at the interface
between paleobiology and population biology. This problem is probably more
evident in physical anthropology than in the other biological sciences
because the paleo-anthropologists and the primatologists find themselves
together in the same field. Paleobiologists must define species as
morphospecies because morphology is really all they have to work with.
Population biologists generally use a definition that looks more like
Mayr's biological species concept because they can use information on
biogeographic distributions and aspects of the phenotype that do not
fossilize well. This leads to the use of conflicting species definitions
when one examines the transition from the relatively recent fossil record
to extant species. It would be great if someone could (or has) develop a
consistent way of looking at species then and now. If anyone knows that
such a thing has been done, I for one would appreciate a posting with the

Guy Hoelzer
Dept. of Biology
University of Nevada Reno
Reno, NV 89557