HUMAN EVOLUTION

Since scientists developed the ability to decode the genome and compare the genetic makeup of species, some people have been stunned to learn that about 98.5% of the genes in people and chimpanzees are identical. This finding means chimps are the closest living biological relatives to humans, but it does not mean that humans evolved from chimps. What it does indicate is that humans share a common ancestor with modern African apes (i.e., gorillas and chimpanzees), making us very, very distant cousins. We are therefore related to these other living primates, but we did not descend from them.
Modern humans differ from apes in many significant ways. Human brains are larger and more complex; people have elaborate forms of communication and culture; and people habitually walk upright, can manipulate very small objects, and can speak.
Our Common Ancestora
Most scientists believe our common ancestor existed 5 to 8 million years ago. Then two species broke off into separate lineages, one ultimately evolving into gorillas and chimps, the other evolving into early humans called hominids . In the millions of years that followed, at least a dozen different species of humanlike creatures have existed, reflected in the fossil discoveries of paleoanthropologists , although many of these species are close relatives but not actual ancestors of modern humans.

In fact, the fossil record does not represent a straight line of ancestry at all; many of these early hominids left no descendents and simply died out. Still others are most likely direct ancestors of modern humans or Homo sapiens. While scientists still do not know the total number of hominid species that existed, because new fossils are discovered every decade, the story of human evolution becomes clearer all the time.