Chapter 15: Hominin evolution
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Chapter 15: Hominin evolution






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Chapter 15: Hominin evolution Chapter 15: Hominin evolution Presentation Transcript

  • Hominin evolution Chapter 15
  • Classification of humansK AnimaliaP ChordataC Mammalia 3 middle ear bones, diaphragm, fur / hair, teeth , one lower jaw bone, mammary glands (Sub-class; Eutheria)O Primates 5 digits with opposable thumbs/big toes, flat nails & sensitive to touch large forward-facing eyes = stereoscopic vision, cones for colour & protective outer socket bone flexible skeleton for life in trees, large brains relative to body size social long gestation periods (more fetal brain growth), provide parental care (Superfamily; Hominoidea)F Hominidae (Subfamily; Homininae) Hominins are bipedal locomotion (erect-walking), only humans and extinct ancestors. position of foramen magnum (p.566), angle between femur & tibia (p. 570) and shape of pelvis (p.568)G Homo Different from Australopith ancestors because; Reduction in size of teeth, increase in brain size, shortening of face & behavioural differencesS Sapiens Whites of eyes - can tell if someone is looking at you
  • Tuang child Lucy
  • AustralopithecusGraciles RobustsA. anamensis A. robustusA. afarensis A. boisei ParanthropusA. africanus A. aethiopicusPossibly ancestral to the human line Cousins of the human lineBrain size: about 400ml Brain size: about 500mlLarge molars , larger canines (Herbivores) Very large molars (Herbivores)Rounded top of skull Bony crest on top of skull of malesAdult height: 1.4 – 1.5m (male) Adult height: 1.3 – 1.4m (male) 1.0 – 1.2m (female) 1.0 – 1.3m (female)Australopithecus ParanthropusA. anamensis P. robustusA. afarensis P. boiseiA. africanus P. Aethiopicus
  • Lucy (3.2 Myr old)• Found 1974 in the Afar Triangle in Ethiopia by Donald Johanson• Australopithecus afarensis• Approx 1m tall when standing on 2 feet – Standing taller meant they could see further but not faster or safer – But... save a little bit of energy and therefore may have reared more young – Walking also frees up chest muscles to help with development of speech
  • Taung child (2.2 Myr old)• November 1924 Cape Province, South Africa - importance recognised in 1984• Raymond Dart (Aussie professor of Anatomy)• Cranium & Mandible (jaw) possessed both ape- like and human-like features: – concluded it was an infant from an intermediate species – classified it as Australopithecus africanus (new species)• Position of foramen magnum, Dart concluded that the Tuang child walked upright
  • What was happening 6 Myr ago?• All came about because rainforests were dying out and grasslands were prominent• due to tectonic plates of India & Asia colliding--> poles freezing over --> less water available --> development of the African Savannah• Spent more time on the ground & less in trees
  • HOMOhabilis history hrudolfensis reconstructs rergaster everything eheidelbergensis however herectus evolution eneanderthalensis never nsapiens seems (to) sflorensis flow f
  • ~ 2-3 Myr ago• More variation amongst upright apes (transitional species)Paranthropus boisei ~2.2 Myr old• roots of tall reeds & termites• couldnt build shelters decreasing tooth size Australopithecus Homo Increasing brain sizeHomo rudolfensis ~ 2.6 Myr ago• scavengersHomo habilis ~2.4 Myr old• scavengers & jack of all trades• made use of first primitive stone tools (Oldowan tools; scrapers, cutters & choppers)• could therefore live off a huge variety of foods• eating meat lead to brain development (half as big again, as boisei)• Oldest Homo fossil is dated back to 2.4 Myr ago
  • ~ 1.6 Myr agoHomo erectus• Brain size: 900ml (intelligence & planning) – Controlled use of fire – Crafting of more elaborate stone tools – Evidence of systematic hunting• Make sounds (no spoken language) – Vertebrae suggests that less nerve tissue in spinal cord -> lack of fine muscle control of breathing that is necessary for speech
  • 1.8 million years agoHomo ergaster• Same as habilis (and thought to have coexisted) but from east Africa• First to be able to piece together information from the world around them• First to make hand axes (made by hitting a core stone with a hammer stone)• Demonstrated ability to learn from each other – as shown by many generations making the same tools• Big brains used to understand one another (uses lots of Energy) – families and friends worked together eg: finding, stalking, killing, sharing food• It was the Homo ergaster who left Africa and crossed the Middle East into Asia (which took thousands of years)• When they were discovered, they were now known as Homo erectus• 1 million years later – Homo ergaster has shown no development. – stone hand axes were still used (not even spears)
  • 40‘000 – 400‘000 years agoHomo Heidelbergensis• Intermediate between H. erectus & H. sapiens• Large brain size: 1100-1400ml• Tall: around 1.8m• More muscular than humansHomo Neanderthalis• Europe• Short limbs - decreasing SA:Vol ratio - prevent heat loss• Wide nose stopped them from sweating• Enduring - many fractures found in fossilised bones• Tolerant to pain• Brains were nearly as big as ours• Anticipation of events (better understanding of selves) ie: childbirth• Relationships were more developed
  • Neanderthals vs Modern humans• mtDNA varies by an average of 27 bases• most human mtDNA will vary only an average of 8 bases-> therefore - they were / are a different species• diverged from the line that gave rise to Homo sapiens about 500-600 000 years ago• co-existed with Homo sapiens for tens of thousands of years before extinction• no interbreeding during that time (separate gene pools)
  • ~ 18‘000 years agoHomo floresiensis• Small (around 1m), Brain size: 380ml• Close to us - similar proportions of brain size to body• Youngest fossils to be found• Alive at the same time as Homo Sapiens (and after Neanderthals)
  • ~ 130‘000 years ago - presentHomo sapiens• Avarage brain size: 1350 – 1400ml• Steep foreheads• Short, high, narrow skulls• Brow ridges small or absent• Small eye sockets• Pointed chin• No gap between 3rd molar and jawbone
  • Out of Africa / Regional continuity Out of Africa hypothesis Regional continuity hypothesis Modern humans should appear first in Modern humans should appear Africa and only later in other parts of the throughout Africa, Asia and Europe during world the same period Transitional forms from ancestral to Transitional forms should be found in modern humans should be found only in Africa, Asia and Europe Africa Variation in mtDNA should be greater in Variation in mtDNA should be about equal African populations than in other in human populations from all regions of populations the Old World• mtDNA studies strongly support the „Out of Africa“ hypothesis
  • Changes in human population• Biological evolution (lactose tolerance, body shape)• Cultural evolution – Changes in human societies over time where those changes are socially transmitted• Technological evolution