ANT 1 Lecture Notes - Lecture 26: Body Proportions, Homo Ergaster, Stabilizing Selection
Document Summary
Piltdown ( discovered in english 1912), forgery not exposed until 1953. Appearance of species adapted to more open environments. Bipedalism may have been an adaptation to forest fragmentation. Middle miocene: foraging mainly within large forest patches. And features first useful for one reason could be exapted for different purpose later. Allows body to have center of gravity. At least partly developmental plasticity (easily molded) Human arch is like a shock absorber. Humans: cranium sitting more straight on top of body -> selection for bipedalism. Orrorin tugenensis has derived features of thigh bone. Ardipithecus kadabba has derived features of toes. Ancestral body size sexual dimorphic, but lack of canine sexual dimorphism (derived) Ancestral early development pattern (m1 eruption ~3, first molar erupted around 3yo) Mixture of derived & ancestral dental/facial features. E. g. prognathic lower face (jutting out) & pre-canine gap like chimps. E. g. smaller front teeth & larger/more enameled molars than chimps (eating more seeds, nuts, tubers)
