05.03 Primate Evolution
Homo sapiens 195,000 years ago to present
First appeared about 195,000 years ago. Forehead rises sharply, eyebrow ridges are very small or more usually absent, and the chin is prominent. Tooth size has continued to decrease over the past 100,000 years. About 40,000 years ago, artifacts of tools showed an increase in sophistication, using a wider variety of raw materials such as bone and antler. Fine artwork, in the form of decorated tools, beads, ivory carvings of humans and animals, clay figurines, musical instruments, and cave paintings, appeared over the next 20,000 years. Scientists traced the source of all human mitochondrial DNA back to common African ancestors only 200,000 years ago.
Homo erectus 1.6 million to 300,000 years ago
First hominid species to migrate out of Africa into Asia and Europe. A descendent of Homo habilis, but was taller with a larger brain capacity. Like H. habilis, the H. erectus face has protruding jaws with large molars, no chin, thick brow ridges, and a long, low skull. Lived in huts or caves, clothed themselves in animal skins, and designed more elaborate tools than earlier hominid species. Some populations in Africa, Asia, Europe, and Australia gave rise to regionally diverse descendents with larger brains.
Homo habilis 2 million to 1.5 mya
Had a significantly larger brain than the Australopithecus species. The name means "handy man," because the remains are often found with primitive stone tools. First time we find tools scattered with the remains of a particular species. The face was still primitive in appearance, with a protruding jaw, large molars, and no chin. Some remains show evidence of the structures necessary for speech, so it is possible that populations developed a rudimentary language. Coexisted for nearly 1 million years with the smaller-brained Australopithecus species.
Homo neanderthalensis 130,000 to 35,000 years ago
Lived in cold climates of Europe, the Middle East, and parts of Asia. Heavy brow ridges, projecting jaws, and less pronounced chins than modern humans, but their brain cavities and body bulk were actually greater than ours. Brain cavity is longer and lower than that of modern humans, with a marked bulge at the back of the skull. Skilled toolmakers and had strong social relationships. A large number of tools and weapons have been found with their remains, more advanced than those of H. erectus. Formidable hunters and are the first people known to have buried their dead, with the oldest known burial site being about 100,000 years old. DNA evidence indicates that they were evolutionary dead ends, going extinct around 35,000 years ago.
Austalopithecus africanus 3 million to 1 mya
Walked upright and foraged on the African savannah. Slightly larger than A. afarensis, with a body size about that of the modern chimpanzee, but with a larger brain. Brains were only about one-third the size of a modern human's brain. The jaw was fully parabolic like modern humans', but the teeth were still much larger. Two forms of A. africanus existed, one slender and the other more robust, leading some paleoanthropologists to believe that they may have been two separate species.
Australopithecus afarensis 3.6 million to 2.8 million years ago
Walked upright but retained many apelike traits, such as curved toes. Only about one meter tall, with a small skull that held a brain about the size of a softball. Had an apelike face with a low forehead, a bony ridge over the eyes, a flat nose, and no chin. Had a forward-projecting jaw with teeth that were larger and more pointed than those of modern-day humans but smaller than those of ancient and modern great apes. The shape of the jaw is between the rectangular shape of apes and the parabolic shape of humans.