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20 Cards in this Set
- Front
- Back
What is a hominin? What two characteristics set it apart?
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A fossil specimen more closely related to modern humans than to modern chimps
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Which primitive Miocene ape is thought to be the last living ancestor of the hominoids?
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Preconsul (~19 mya)
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What are the steps that create a fossil?
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Organism must become buried in the sediment, bone or teeth must mineralize, surrounding sediment must harden
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By what percentage does human DNA differ from that of chimps?
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~ 1.6%
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What are some skeletal adaptations for bipedalism compared to ape anatomy?
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Human spine is S-shaped and exits from the center, pelvis is bowl-shaped, femurs angle inward, knees support more weight
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What are the two forms of australopithecines? Examples?
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Gracile (lightly built)-- A. afarensis (East Africa), A. africanus (South Africa)
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Who was Lucy?
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Australopithecus afarensis, bipedal, 3.2 mya, 3.5 ft tall/105 lbs.
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Who was Laetoli?
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3.6 mya, East Africa
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What were the Ardipithecus ramidus? Characteristics?
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The first undisputed biped (4.4 mya) with an ape-sized brain and grasping big toe
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What is the order of the hominid phylogeny beginning at 7 mya?
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Sahelanthropus tchadensis (7 mya in Chad), Orrorin tugenensis (6 mya in E. Africa), Ardipithecus ramidus(~5mya), A. afarensis (~3mya), A. africanus (~2.5 mya), A. robustus/A. boisei (~2mya)
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What are some theories that have been used to explain bipedalism as an adaptation?
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Bipedalism reduces the surface area exposed to the radiation from the sun and leads to more wind exposure (standing upright=taller, so more wind)
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How has the cost of transport in terms of O2 and body mass varied across terrestrial species?
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See graph--quadrupedal and bipedal chimps use significantly more O2 than humans (especially when it comes to running)
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What are the 2 main trends in the genus Homo?
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Reduced face, jaws, and teeth in addition to an enlarged brain (encephalization)
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What are traits of Homo habilis? Why so significant?
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~2.3-1.5 mya, 600-800 cc brain volume, slight increase in body size
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What are traits of Homo erectus/ergaster? Why significant?
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~1.8-0.6 mya, 1000 cc brain volume, increase in body size (5.5-6 ft tall), longer legs relative to arms, small teeth, Acheulean technology--more spear-like
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What is the order of species in human evolution?
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Carpilestes simpsoni, Darwineus micelae, Aegypithecus zeuxis, Proconsul Africanus,**start here: Ardepithecus Ramidus ("Ardy,"4.4 mya, one of first bipedal, more human facial features), Australepithecus afarensis (lucy & leatoli), H. habilus--> H. ergaster/erectus--> H. heidelbergensis--> H. Neanderthalsis (in Europe) AND H. sapiens (in Africa)
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What are traits of the Homo neanderthalensis? What happened to them?
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Europe/Western Asia, 400,000-30,000 ya, 5'3"-5'6", 110-140 lbs., heavily muscular, big 1450 cc brains, yet limited cultural and technological sophistication
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What are traits of Homo sapiens? How did their technological sophistication improve?
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Origin: ~200,000-100,000 ya in Africa, migrated out ~60,000 ya and mostly replaced existing hominids
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Why is mitochondrial DNA so significant? What does it reveal in terms of modern humans?
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Accumulated mutations 10x faster than nuclear DNA, only inherited through the mother
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Why did modern humans out-compete neanderthals?
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Superior cultural transmission of knowledge/innovation (?), language (changes in vocal tract anatomy & brain organization), extension of lifespan, increased population density
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