8 7 6 5 4 3 2 1 Millions of years ago
Chimpanzees
Bonobos
Sahelanthropus tchadensis
Orrorin tugenensis
Ardipithecus
Australopithecus anamensis
Australopithecus afarensis
Australopithecus garhi
Australopithecus africanus
Paranthropus
Homo habilis
Homo erectus
Homo neanderthalensis
Homo heldelbergensis
Homo sapiens
Adaptations
for walking
bipedally,
smaller canine
teeth
Enlarged cheek
teeth and jaws
Massive cheek teeth and jaws,
enlarged chewing muscles
Slightly larger brain (600 cc), more vertical face
without a snout, fingers capable of precision grip,
ability to make simple stone tools for processing
food Including meat
Smaller jaws and cheek teeth, long legs and arched feet
well-sulted for long-distance walking and running, larger
brain (Homo erectus brains range from 650 cc to 1200 cc)
Sophisticated stone flakes, tools for hunting,
brain size Increases to 1200 cc
Large brain (1400 cc), small face tucked below brain case,
rounded cranial vault, small brow-ridges, capadty for art,
symbolic thought, full-blown language
Hominid phylogeny from The Tangled Bank, used with permission of the author, Carl
Zimmer, and publisher, Roberts & Company, Greenwood Village, Colorado.