If Joe (a member of a ring species) were counterfactually in a different population of his ring species with different reproductive mechanisms, he would still be a member of his species so long as he remains in its lineage and gene pool.
The biological systems and processes that allow organisms to produce offspring, which can vary between different populations.
counterfactual(Modal logic and epistemology)
A conditional statement concerning what would be the case if some antecedent condition were true, evaluated across possible worlds; contraposition does not hold in general for counterfactuals.
ring species(Used as a counterexample to intrinsic essentialism about species; distant populations have different reproductive mechanisms.)
A geographic ring of populations such that organisms in contiguous populations can successfully mate, but organisms in populations at distant links in the ring cannot successfully mate.
To reinforce this point, consider which aspects of an organism can be changed while it remains a member of the same species, and which aspects cannot be changed. The intrinsic reproductive mechanisms within the organisms of a species can be changed, but being part of the same lineage or gene pool cannot be changed. To make this more concrete consider the case of ring species. A ring species consists of a geographic ring of populations such that organisms in contiguous populations can successfull