Well you can reproduce between species. A liger is a cross between a tiger and a lion. A mule is a cross between a donkey and a horse. There are several species that can cross breed. And sometimes the offspring can breed as well. A human may have bred to species that pre-dated humans. Or species that spawned from the origin of humans. We know that neanderthals existed at the same time as humans. We don’t know if they could breed with humans. Or if there were other species that could cross with humans which would explain races and other genetic differences in people even within races.
Darwin suggests that traits of an animal will make that animal more fit than another within a species or even between species. But Darwin does not explain where the traits come form. How the evolution happens. If there is no first human, but rather a group of Humanoids that have the ability to mate with other similar species then traits can get introduced and reintroduced as different creatures mate with others not exactly within their own species. When one element of the mix is added or deleted, you can have a species, a race, or an identifiable subgroup like Swedes are different from Greeks even though both are Caucasians.
The idea is that evolution does not mean that there was a first man and first women. It means that there are almost first humans who mate with humans and less than humans for thousands of years until they create a group that is relatively defined and successful. The less successful beings disappear.
ugh, I ain't never gownta get that drunk again. Woke up next to the ugliest gal I ever did see. Thought I was gonna have ta naw my hand off to get away.
Now the less successful groups are protected, celebrated and subsidized. Idocracy here we come.