Final answer:
Apes evolved in Africa around 25 million years ago and began to migrate out of Africa around 2 million years ago, with Homo ergaster and later Homo sapiens spreading globally. Homo sapiens started leaving Africa approximately 100,000 years ago, eventually becoming the dominant human species.
Step-by-step explanation:
The Expansion of Apes and Early Humans Out of Africa
Apes, including the ancestors of humans, originated in Africa. Around 25 million years ago, apes evolved from catarrhines in Africa and began differentiating from monkeys. Unlike monkeys, apes, such as gibbons, orangutans, chimpanzees, gorillas, and humans, are generally larger and lack a tail. They exhibit more advanced cognitive abilities and have larger brains relative to body size. The fossil record shows that by 40,000 years ago, modern humans had spread from Africa to Asia, Europe, and Australia.
Early human movement out of Africa dates back to about 2 million years ago, with Homo ergaster potentially being one of the first to migrate out of the African continent. By 1.75 million years ago, this human ancestor had moved northward into Eurasia, and by 1.6 million years ago, Homo erectus reached as far as Java. Australopithecus, another essential link in human evolution, lived about 4 million years ago and went extinct around 2 million years ago.
Eventually, Homo sapiens emerged in Africa approximately 200,000 years ago, later expanding out of Africa and commencing a global migration about 100,000 years ago. This movement took early humans to the far reaches of the globe, replacing other human species and becoming the sole surviving human species. Genetic and fossil evidence suggests that the common ancestor of humans and chimpanzees lived between 5 and 7 million years ago, with Sahelanthropus tchadensis from Chad, estimated to be about 7 million years old, as a possible example of these early hominids.