[Taxacom] Reproducibility of descriptive data

[Stephen Thorpe]

>So how often do they have to interbreed and produce how fertile an offspring?

This is a difficult question, but that doesn't mean that it doesn't have an answer! Analogy: Australia (forget Tasmania and smaller islands) has natural boundaries (unlike U.S.A.), but the boundaries are somewhat fuzzy (or "swooshy": the tide goes in and out). So the answer to your question isn't necessarily perfectly precise either. Nevertheless, there is a BIG difference between species (Australia) and genera (U.S.A.)


>And what if the isolating mechanism is the Atlantic Ocean - only then some foolish biped comes along, brings two things together than were once very effectively isolated by the ocean and find they are interfertile! Does that negate the impact of the accumulation of other genetic differences between them?

If they haven't diverged enough to maintain "reproductive integrity" [what a quaint term!] when brought together under natural conditions, then they aren't distinct species! It doesn't negate the genetic differences between them, it just means the differences are not significant enough to count as distinct species...


________________________________________
From: Mary Barkworth [Mary at biology.usu.edu]
Sent: Thursday, 10 September 2009 11:18 a.m.
To: Stephen Thorpe; TAXACOM
Subject: RE: [Taxacom] Reproducibility of descriptive data

So how often do they have to interbreed and produce how fertile an
offspring? And what if the isolating mechanism is the Atlantic Ocean -
only then some foolish biped comes along, brings two things together
than were once very effectively isolated by the ocean and find they are
interfertile! Does that negate the impact of the accumulation of other
genetic differences between them?
Mary