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Re: Ancestors... (was Re: Stratigraphy, biogeography & cladograms)

In a message dated 1/20/99 10:58:43 AM EST, bsaurus@bellatlantic.net writes:

<< If species
 is also a human construct, what would be the definition? >>

It is not a "human" construct, it is a contingent construct: a species is the
cross-section of a lineage at a particular time. All the extant species that
we see around us today are the cross-sections of lineages (by the "present")
that go back in time to the first life forms (and extend into the indefinite
future to life forms as yet unevolved). Likewise, fossils represent species
that are the cross-sections of lineages at earlier times. A definition of
species that doesn't incorporate time is headed for trouble.