Despite the protests of creationists and their intellectual allies, science has long taught that human beings are just another kind of animal, but most of the time this seems like a technicality. It's not just the clear differences--language, civilization, technology, that set us apart. Even basic biology suggests that humanity has special status. Virtually every other type of animal comes in multiple varieties- primates (guerrillas, orangutans, chimpanzee , etc.) antelopes(deer, elk, moose, goats, etc.)fish, snakes and we can go on and on.
But there's now only one species of human on the planet, and in the simplified view of evolution most of us have, that's all there has ever been. A few million years ago, most of scientists think, the half-ape know as Lucy appeared in Africa; she was a less ape like creature, who evolved into something more human like. Finally, after a few more changes, Homo Sapiens appeared. Except for that odd side branch know as the Neanderthals, the path from proto-apes to modern humans is commonly seen as a succession of new and improved species taking the place of worn-out evolutionary clunkers.
It's a satisfying, if slightly chauvinistic tale, but experts in human evolution have known for years that it is dead wrong. The evolution of a successful animal species almost always involves trial and error, false starts and failed experiments. "Humans are no exception to this," says anthropologist Ian Tatterasll of the American Museum of Natural History in New York City, "no matter what we like to think.".
True, were descend from a creature that split off from the apes millions years age. But subsequent events were hardly a steady march from primitivism to perfection. Human evolution nearly resembles an elimination tournament. At just about any given moment in the history of our family tree included several species of hominids( erect, upright, walking).