GEOG20009 Lecture Notes - Lecture 20: Homo Habilis, Canine Tooth, Pelvimetry
15 May 2018
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LECTURE 20: HUMAN EVOLUTION
• Palaeoanthropology: study of ancient man
What makes us human?
• Biology and culture
• Bipedalism
• Omnivory
• Large brain relative to body size
• Environmental manipulation
• Symbolic expression: art, ritual, religion
• Language
EVOLUTION OF THE EARLY HUMAN
• 6-7 Ma – shared DNA with chimpanzee – common ancestor in the past
o DNA evidence can be used to estimate when species diverged
• Fossil Record: early hominin sites in Africa
o Main sites: GEA Rift Valley and South African sites
• Hominin: all humans and our bipedal ancestors
o 3 candidates for first species of hominin
Bipedalism
• Obligate bipedalism (walking on 2 legs) – first thing that separates use from apes
• Advantage: frees our hands, effective long distance locomotion
• Easier to see predators & prey on savannah
• Theory: when savannahs replaces forest due to changing climate in late Miocene – moved from trees to ground
• Adaptations for bipedalism: femur, knee joint, shape of foot, spine & pelvis shape
Language
• All animals communicate, only humans use symbolic language
• Symbolic, infinite combinations, concepts of time (past, present, future)
• Area of the brain control language, language gene (FOXP2)
3 candidates for first species of Hominin
Sahelanthopus
tchadensis
• Found in Chad
• 6-7 Ma, may be common ancestor to humans and chimps
• Ape-like: sloping face, large supraorbital ridges, small brain
• Human-like: small canine teeth, bipedal
Orronin
tugenensis
• 6 Ma, fragmentary remains
• Ape-like: climbed trees (curved finger bones)
• Human-like: bipedal, small teeth, thick enamel
Ardipithecus
kadabba
• Found in Ethiopia
• 5.8-5.2 Ma
• Ape-like: similar size to modern chimp, fibrous diet
• Human-like: bipedal
Adaptations Over Time
• Bipedalism
• Tools, fire use, clothes
• Brain begins to grow (preceding bipedalism)
• Changing of adaptations from tree-climbing to walking – due to change in environment from forest to grasslands
THE HOMO GENUS
• Larger brain, jaw and teeth smaller – through movement of species from oldest to newest Homo
• Oldest evidence for Homo 2.8 Ma
• Cooling and drying of climate coincides with first members of Homo genus in fossil record
• Evidence of climate change providing niches which led to Homo genus
• Homo habilis: first species of homo (2.4-1.4Ma), 1.3m tall, 32kgs, enlarged brain capacity, longer arms, shorter legs
o Associated with use of stone tools – scavenging, rather than hunting
Document Summary
What makes us human: biology and culture, bipedalism, omnivory. 6-7 ma shared dna with chimpanzee common ancestor in the past: dna evidence can be used to estimate when species diverged. Fossil record: early hominin sites in africa: main sites: gea rift valley and south african sites, hominin: all humans and our bipedal ancestors, 3 candidates for first species of hominin. Bipedalism: obligate bipedalism (walking on 2 legs) first thing that separates use from apes, advantage: frees our hands, effective long distance locomotion, adaptations for bipedalism: femur, knee joint, shape of foot, spine & pelvis shape. Easier to see predators & prey on savannah. Theory: when savannahs replaces forest due to changing climate in late miocene moved from trees to ground. Language: all animals communicate, only humans use symbolic language, area of the brain control language, language gene (foxp2) Symbolic, infinite combinations, concepts of time (past, present, future) Adaptations over time: bipedalism, brain begins to grow (preceding bipedalism)
