How do new species arise, of hominids or any organism?

First, the human species most likely arose only a hundred thousand years or so ago - the day before yesterday in evolutionary time.

Speciation is the evolutionary process by which new biological species arise.

Saltationism was the idea that new species arise as a result of large mutations.

Also, Darwin did not offer a precise explanation of how new species arise.

"It relates to the question of how these unisexual species arise in the first place."

Many species probably arose as the human line evolved, but only one now remains.

The species probably arose in the tropical reaches of southern Asia, and later spread across its current range.

The five species are genetically distinct, and probably arose between 5 and 7 million years ago.