When a Parent Becomes a Daughter

[Vidhyanath Rao]

<JoatSimeon at aol.com> wrote

>>rao.3 at osu.edu writes:

>>> << Wouldn't the rise of new species be a better parallel to the rise of
>>> new languages? Ancestral species can exist at the same time as a species
>>> that has split off.

> -- not generally.

The claim says 'can'. To give on example: Polar bears are generally
thought to have descended from brown bears or grizzlies. Should we set
up two species for the latter, one before and one after the split, just
because of the split?

Homo habilis seems to have survived till about 30000 BP. So it
co-existed with a lot of other species in Homo which are usually derived
from H. habilis or a descendent species.

> Eg., we and the chimps (and gorillas and bonobos) are descended
> from a common ancestor, and chimps are much more _like_ that
> common ancestor, but we can't be said to be descended from chimps.

I fail to understand the logic. You cannot deny the existence of
counter-examples by giving examples.

BTW, it is not at all clear that chimps are more like the common
ancestor. There was an article in New Scientist several years ago which
pointed out similarities between Homo and the common ancestor and
suggested, tongue partly in cheek, that chimps were descended from
humans. [The title was something like ``When we took to the trees''.
This was a cover story.]