FactSentinel

Humans did not evolve from modern monkeys. Humans and today's monkeys share a common ancestor, but that ancestor was neither a human nor a modern monkey. Scientific consensus holds that the lineages leading to humans and to living monkeys split millions of years ago, and each has been evolving independently ever since. Old World monkeys such as baboons and macaques diverged from the line leading to apes and humans roughly 25 to 30 million years ago. Humans are more closely related to chimpanzees and bonobos, with the human and chimpanzee lineages separating about 6 to 8 million years ago.

The evidence comes from several independent fields. Fossils of early hominins, including Australopithecus and Homo species, document gradual changes in brain size, posture, and teeth. Genetic comparisons show humans share about 98 to 99 percent of their DNA sequence with chimpanzees, a much closer match than with any monkey. Shared genetic markers, such as matching fusion points in chromosomes, point to a common ancestry that can be dated with molecular clock methods.

The confusion often comes from picturing evolution as a ladder, with monkeys at the bottom and humans at the top. Evolution is better described as a branching tree. Living monkeys are not earlier versions of humans. They are modern species that have adapted to their own environments over just as many years. A helpful comparison is that cousins share grandparents without one being descended from the other. Humans are also apes, not descendants of monkeys.