Speaker
Description
We introduce the so-called identical ancestor point axiom, a formalization (under the simplifying assumption that life does not go extinct) of Hennig's non-splitting criterion for species. This axiom states that for any organism in any species, either the species contains at most finitely many descendants of that organism, or else the species contains at most finitely many non-descendants of that organism. We argue this axiom is plausible for species. We show that, together with a mild convexity axiom, this reduces the subjective nature of species definition. We call connected sets satisfying these two axioms "specieslike clusters." We consider the question of identifying a set of biologically plausible constraints that would guarantee every organism inhabits a maximal specieslike cluster subject to those constraints. We provide one such set consisting of two constraints, and show that no proper subset thereof suffices. Finally, we sketch two new applications of these ideas to biology.
