Biological/Physical Anthropology: Human Evolution, Primates, Variation and Adaptation
Biological anthropology tests evolutionary reasoning: how primates and hominins are classified, how fossils are interpreted, and how human variation is explained without racial typology. It combines genetics, primatology, paleoanthropology, and human biology.
Core concepts
- Natural selection requires variation, heritability, and differential reproductive success; mutation, gene flow, and genetic drift also cause change.
- Primate traits include grasping hands and feet, nails, forward-facing eyes, stereoscopic vision, reduced olfaction, large brains, and prolonged parental care. Prosimians, monkeys, apes, and humans are not a single ladder.
- Hominin trends include bipedalism, encephalization, reduced canine size, and tool use. Bipedalism is read from the foramen magnum position, pelvic shape, and femur angle.
- Major taxa include Australopithecus, Homo habilis, Homo erectus, Homo sapiens, and Neanderthals. Neanderthals were cold-adapted and made Mousterian tools; they were not ancestral to modern humans.
- Human variation is distributed as clines and polymorphisms. Race is a social category, not a valid biological subdivision. Adaptations include Bergmann and Allen rules, sickle-cell polymorphism, lactose persistence, and high-altitude physiology.
Worked example
In malarial regions, HbS heterozygotes have greater survival than HbAA homozygotes, while HbSS causes sickle-cell disease. The allele persists because heterozygote advantage balances selection against homozygotes. In non-malarial regions, selection against HbS is not balanced, so frequency tends to fall. The reasoning links genotype, environment, and fitness rather than labeling a population inferior.
Traps
Avoid Lamarckian inheritance of acquired traits, a linear march of progress, and the term missing link. A larger brain alone does not prove greater intelligence, and cultural labels must not be treated as biological races.