definition of macroevolution

Bill Hamilton (hamilton@predator.cs.gmr.com)
Mon, 3 Jun 1996 10:22:58 -0400

In a private response to comments I made on the reflector, Stephen Jones
challenged my remark to the effect that speciation ought to be considered
macroevolution. His response was a long quotation from Gould, which I
confess I haven't read yet.

I have no desire to introduce nonstandard definitions, but my question to
the group is: How well-established is the distinction between micro- and
macro-evolution? My rationale for calling speciation macroevolution was
that speciation establishes a new population which cannot interbreed with
an older population. This is an element of irreversibility not present in
normal genetic variations which do not result in speciation. If there were
no speciation, it seems to me there would be no macroevolution. Therefore
it seems reasonable to designate speciation as the elementary, first step
of macroevolution.

But if I'm out in left field, I would appreciate it if some of you experts
would let me know.

Thanks.

Bill Hamilton | Chassis & Vehicle Systems
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