ANTH 1006: EXAM 1: HOMINIZATION
52 Cards in this Set
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Hominization
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The process of becoming human
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Speciation
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Formation of distinct species by genetic divergence leading to reproductive isolation
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allopatric speciation
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Physical barrier to gene flow occurs
Reproductive isolation develops
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Human Adaptive Trends
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Terrestrial Environment
Omnivorous Diet
Dependence on Culture
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Physical Trends
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Structure of the Pelvis
Foramen Magnum Under Skull
Spinal cord enters through base of the skull
Narrower Rib Cage; Multiple Curves of Spine
Longer Legs; Shorter Arms; Position of Big Toe
Mechanical Balance
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Why Bipedalism
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Thermoregulation
Vision over tall grass
Free hands
Sexual bonding
Longer periods of walking
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Why omnivorous diet?
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Important role in culture
Evolution of Big Brains
Sharing the gift of meat
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Structural Changes in the Rib Cage
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Pyramid-Shaped To Barrel-Shaped
Larger Lungs
Smaller Digestive Organs
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Enlargement of the brain
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Larger and more complex
Survival
Increased cranial capacity
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Fossilization
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Preserved remains of animals, plants and other organisms
Living Tissue to Stone!
Exact Replication
Rare
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Taphonomy
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The science of burial
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Agents of Fossilization
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Biologic: Carnivores?
Geologic: Erosion, Alluvial Transport
Behavioral: Hominin butchering, home base
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2 levels of
Biological Taxonomic Classification
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Molecular
Physical
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2 types of
Geological Dating
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Relative: superimposition
Absolute: Radiometric
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Paleoenvironmental Reconstruction
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Determination of a prehistoric environment such as:
Geology
Water Sources
Climatic Conditions
Land Forms
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Fossil evidence of culture
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Behavior
Degree of Complexity
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Scars of Human Evolution
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Herniated Disc
Sciatica
Osteoarthritis
Crooked Teeth
Flat feet
Difficult childbirth
Appendicitis
Vestigial structures
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Continental Drift
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Breaking of Pangea
200 MYA
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Plate Techtonics
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Division of the world, causes different climates
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How did primates evolve from mammals?
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Arboreal Theory- mammals move to trees
Visual Predation Theory- need to see better for food capture
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Arboreal Insectivores
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First mammals to live in trees
80 MYA
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Archaic Primates
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“Leaping”
1st true primates
60-55 MYA
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First Monkey-like Creatures
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Originated in Africa
50 MYA
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New World Monkeys
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More teeth
Flatter nose, side facing nostrils
Prehensile tails
Monogamous pairing
Few Fossils
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Aegyptopithecus
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Egyptian
First true apes
30 MYA
Cat sized
Forward eyes
Larger brain
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U-Shaped Dental Arcade
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Ape= U shaped
Human= Parabola
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5-Y Cusp Pattern
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Lower molars
Similar in humans and apes
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Asian / African Primate Split
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14 – 8 MYA
Asia: Unbroken Forests: Orangutans, Gibbons
Africa: Island or Residual Forests: Chimps, Gorillas
Plains or Savannas: Humans
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Kenya Fossil Discovery
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Dr. McBrearty
Fossil Chimpanzees Teeth
Rift Valley, East Africa
780 to 130 KYA
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Miocene Asian Apes
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24-5 MYA
Time when First Hominins Evolved
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Dryopithecines
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“Oak Ape”
Forests of Eurasia
Orangutans (?)
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Gigantopithecus
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5 MYA to 250,000 YA
Largest Primate ever to Exist
China and Vietnam
Ground Living (?)
“Big Foot” or “Yeti” (?)
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Miocene African Apes
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5 – 8 MYA = Very Few Fossils
After 5 MYA – Stockpile of Fossil
Already Bipedal (?)
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Molecular Clock
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Blood proteins of different primates change at a “Constant Rate”
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When did the common ancestor of chimpanzees and humans live?
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5-7 MYA
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Taxonomic Lumper
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Differences Reflect Diversity of Same Species
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Taxonomic Splitter
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Differences Reflect Separate Taxon (i.e., genus, species)
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Family Homininae
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Bipedal
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Australopithecus
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Small Brained, “gracile”
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Paranthropus
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Small Brained, “robust”
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Homo
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Large Brained, Omnivorous, Behavioral
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Ardipithecus ramidus
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"Ardi"
“Ground ape
5.8 – 4.4 MYA
1993 in Ethiopia
Small brain
Long arms
U-Shaped dental
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Facultative Biped
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Biped on ground
Four legged in trees
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Australopithecus anamensis
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4.2 – 3.9 MYA in Kenya
Lower jaw is ape-like
Tooth Enamel Thicker and Canines Smaller than “Ardi”
Bipedalism
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Australopithecus afarensis
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"Lucy"
3.9 – 2.9 MYA
Legs Short; Arms Long
Definitely Bipedal
Savannah
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Laetoli Footprints
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Tanzania 1974
2 – 3 Individuals
3.6 MYA
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Australopithecus africanus
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3.5 – 2.0 MYA
“Southern African Ape”
Large Molars, Thick Enamel
Incisor Teeth Smaller
Canines Even
Brain Larger
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Taung Baby
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1st Identified Hominid Fossil
1925 South Africa
Dr. Raymond Dart
2.8 MYA
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Paranthropus
(Robust Australopithecines)
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Early Hominins (2.7 – 1.2 MYA)
Evolutionary Dead End
Anatomically Specialized
Massive Jaws and Chewing Mechanisms
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Paranthropus aethiopicus
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East African
2.7 – 2.5 MYA
Huge Jaws
Sagittal Crest
Dish-Shaped Face
Huge Molars, Thick Enamel, Hard-Object Feeding
Small Brain (400 cc)
Savannah
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Paranthropus boisei
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Leakey
2.3 – 1.2 MYA
Descended from aethopicus
East African
Back teeth expanded, Front teeth reduced
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Paranthropus robustus
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South African variant
2.0 – 1.5 YMA
Flat face
Thick jaw
Wide cheekbones
Omnivorous (?)
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ANTH 1006: EXAM 1: HOMINIZATION