Human Evolution and Biological Anthropology
Biological anthropology examines human evolution, genetics, growth, adaptation and the behaviour of non-human primates. The exam tests the hominin sequence, the anatomical markers of bipedalism, evolutionary mechanisms and the difference between relative and absolute dating.
Mechanisms and evidence
Evolution is a change in allele frequencies across generations. The modern synthetic theory combines Darwinian natural selection with Mendelian genetics: mutation creates variation, gene flow and genetic drift alter frequencies, and selection adjusts them to environments. Fossils are dated relatively by stratigraphy and absolutely by radiocarbon (up to about 50,000 years), potassium-argon (volcanic rocks), and thermoluminescence.
Hominin trends
- Bipedalism: anterior foramen magnum, basin-shaped pelvis, valgus knee, arched foot, non-opposable big toe.
- Encephalization: cranial capacity rises from about 400-500 cc in Australopithecus to about 1,350 cc in modern Homo sapiens.
- Dentition: reduced canines, thicker enamel, smaller jaws.
- Culture: Oldowan choppers (Homo habilis), Acheulian handaxes and fire (Homo erectus), Upper Palaeolithic blades and art (Homo sapiens).
Worked example
A fossil has a short, basin-shaped pelvis, an anteriorly placed foramen magnum, small canines and a cranial capacity of 450 cc. The pelvis and foramen magnum indicate habitual bipedalism; the small brain and ape-like canines place it in Australopithecus rather than Homo. Association with stone tools would not by itself make it Homo, because tool use is not a genus-defining trait.
Traps
Avoid 'missing link' language; evolution is a branching bush, not a ladder. Neanderthals are a sister lineage, not direct ancestors of Europeans. Lamarckian inheritance of acquired characters is wrong. A bigger brain is not automatically 'more evolved', and radiocarbon cannot date million-year-old fossils.