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Re: AMARGASAURUS SATTLERI (pretty long)
In a message dated 9/4/00 3:31:30 PM Pacific Daylight Time,
> More directly, can we not assert that each species is the result of changes
> to a different species? If this is true, then it is possible to know by
> observation which species gave rise to the new species, as with those birds
> on isolated islands.
I'm not talking about species here; I'm talking about individuals. Even when
speciation is relatively rapid, the changes from one generation to the next
will appear very slight and usually within the range of individual variation.
If you watch a species split very closely, generation by generation, over
time, there will generally not be any particular point where you can say that
a new species (let alone higher taxon) has emerged. If you only look at
every fifth generation, or better yet every 500th or 5000th, the task of
grouping individuals into species, genera, etc., becomes much easier.