It is worth expanding here, for those who are not familiar with this version of the 'species concept', that it is not just the ability of two different populations to produce offspring that decides whether or not they are conspecific, but also the offspring themselves must be fully fertile and able to produce fertile offspring of their own.Chuck wrote: ↑Thu Feb 13, 2025 1:49 pm Part of the problem with the whole taxonomic model of genus and species is based on flawed, and generally (perhaps grudgingly) accepted, ability for an entity's ability to produce offspring. The problem has long been that there are too many exceptions. Using the "offspring" rule only, there is no difference between O victoriae and O priamus urvilleanus (which, given that urvilleanus is a ssp, suposedly means the species designation of victoriae and urvilleanus are inappropriate.
Hybrids between species are usually either completely infertile or have reduced fertility, particularly if mating with another hybrid from the same parent populations. It is worth noting that often hybrids between closely related species are able to mate successfully with either parent species (known as a 'backcross') and produce fertile offspring, whereas a mating between two of the hybrids produces very few or absolutely no offspring at all. This is the mechanism whereby gene exchange can occur between different species. A good example most people will have heard about is the presence of genes from Neanderthal man in humans, averaging about 5% of the genome. Doubtless this is a result of 'hybrid' offspring then mating with humans and passing on Neanderthal genes to modern humanity.
Adam.