Species are often defined as genetically distinct groups that cannot interbreed, but this line is often blurred. Take for instance an article in the NYT from Monday that explores hybridization. While most hybrids do turn out sterile, is it possible that these animal mash-ups are better suited for intermediate environments than their parents? When put into the context of global climate change, are these hybrids a response to environmental pressures?
Well, I don't think necessarily that natural selection is guiding towards cross species mating because most offspring are not viable; the occurrence of these hybrids in the wild is interesting none the less. The evolutionary context is that viable hybrid offspring could be responsible for some modern day species, perhaps even our own. And that is exciting.