Final answer:
The known hominin species from the Plio-Pleistocene include Australopithecus, H. erectus, Neanderthals, and Denisovans, representing different stages of human evolution and our ancestors or relatives.
Step-by-step explanation:
The hominin species known from the Plio-Pleistocene include Australopithecus, H. erectus, Neanderthals, and Denisovans. These species represent different stages of human evolution and are our ancestors or closely related relatives. For example, Australopithecus was the first evidence of bipedal hominins, and H. erectus is considered to be ancestral to modern humans. Homo habilis, known as "handy man", was an early species in the genus Homo, living about 2.5 to 1.4 million years ago, and is noted for the stone tools found with its remains. Additionally, Homo erectus lived from about 1.9 million to 143,000 years ago and was the first hominin to leave Africa, spreading to other continents.