What did Darwin mean by continuity of species?

-- Rosalind Gildea (frudadre@freenetname.co.uk), October 09, 2001

Answers

There are two distinct questions of continuity when it comes to species. The first is about continuity between *successive* species -- e.g., there is no specific individual about whom one could definitively say that Australopithicus had ended and Homo had begun. The one faded into the next almost imperceptably. Only in hindsight do we say that a given specemin is Australo. and the other Homo (I realize I've use genera rather than species in this example, but you get the point).

The second is about (lack of) continuity between *simultaneously existing* species. Notice that all of the apparently availalbe "phenotypic space" is not occupied -- there is nothing, for instance, "between" horses and cows. There are just the two species, and "space" in between which could in principle be "filled up" by other species, but that, for a combination of contingent historical reasons, isn't in fact.

-- Christopher Green (christo@yorku.ca), October 11, 2001.