Exam 3

• Oligocene Epoch

  • 34-23 mya
  • expansion of grasslands
  • new habitats opening up
• Propliopithecidae

  • early anthropoid
  • true Catarrhines
  • predate cercopithecpdia-Homoinoida split
  • found in africa
• Propliopithecidae Features

  • Large body size
  • sexually dimorphic canine
  • frugivorous
  • quadrupedal (non-leaping) with short robust limbs
  • Diunrnal
  • Small brain
  • long snout
• Platyrrhines to S America

  • ~35 mya
  • Sea level lower
  • North American Hypothesis
  • Atlantic Ocean Crossing Hypothesis (most parsimonious)
  • Antarctica Crossing Hypothesis
  • independent origin Hypothesis
• Miocene Epoch

  • 23-16 mya
  • Initial warming trend then cooling & Drying
  • Major Geological activity (birth Andes, Himalayas & great rift valley)
  • Sea levels drop (expose land bridge Africa & Eurasia)
• Miocene African Monkeys

  • sparse fossil record
  • Genus Victoriapothecis
  • Genus Mesopithecus
• Genus Victoriapithecus

  • quadrapedal
  • Colobus like face
  • Sexually dimporhic
  • Pre-cercopithecidae split
• Genus Mesopithecus

  • replaced Victoriapithecis
  • Colobine
  • Spread into Asia
• Origins of Extant Apes

  • very sparse in africa (gap vs not found)
  • more abundant record in Eurasia
  • Africa-origin hypothesis (not found)
  • Eurasian hypothesis (gap)
• Mosaic Evolution


  different traits evolve independent of each other
• Hominids


  Humans and non great apes, the Hominidae family
• Hominins 


  Humans and ancestors after divergence with african apes
• 3 Major Groups of Hominins

  • Pre-Australopiths ( 6 - 4.4 mya)
  • Australopiths (4.2 - 1.2 mya)
  • Early Homo (2 - 1.4 mya)
• Hominin Characteristics

  • Bipedal Locomotion
  • Large Brains
  • Small generalized teeth
  • Tool making behavior
• Bipedalism key Adaptations

  1. Cranium placement (foramen magnum more centralized)
  2. S-shaped spine
  3. pelvis shape
  4. Valgus Knee (more angled)
  5. Foot shape
• Bipedalsim Benefits

  • Ability to carry
  • Feeding from bushes
  • See out across savannah
  • Thermoregulation (faster cooling)
  • Energetic efficiency
• Bipedalism evolutionary trade-offs

  • Loss of climbing abilites
  • Higher risk of heart attack & stroke
  • Musculoskeletal injuries & strain
  • Obstetric dilemma
• Levels of Bipedalism

  • Facultative Biped(can walk short bouts)
  • Habitual biped (regular locomotion but not specialized morphologicaly)
  • Obligate biped (committed biped with derived traits for walking)
• Big brain evolutionary trade offs

  • Energetically expensive (25% glucose utilization)
  • Slower brain development
• how achieved big brains

  1. Eating more energy dense food
  2. Cooking (reduces energy required for digestion)
  3. Cooperative care ( Slowing development )
• Dental Changes

  • Dental formula 2:1:2:3
  • Smaller generalized teeth
  • smaller canines (no honing complex)
  • thicker molar enamel
• Holotype


  single "type" specimen upon which the description and name of a new species is based
• Sahelanthropus Tchadensis

  • northern Chad
  • 6-7 mya
  • Holotype: Toumai
  • Primitave Features ( Big brow ridge, small brain, post orbital constriction)
  • Derived Features ( small canines, little/no diastema, inferior foramen magnum)
• Orrorin Tugenensis

  • Kenya ( only 13 fossils)
  • 6 mya
  • Primitive Features ( chimp like teeth, small brain, curved hands)
  • Derived Features ( thick enamel, bigger femoral head, longer femoral neck, facultative biped)
• Ardipithecus

  • Ethiopia
  • Ardipithecus Kadabba ( 5.2- 5.8 mya)
  • adipithecus Ramidus (4.4 - 4.2 mya)
  • Primitive Features ( small brain, chimp sized, Prognathic face, flat feet, opposable hallux (toe) , curved hands, longer arms)
  • Derived Features (broad iliac blade, facultative biped, thicker enamel, reduced canines, reduced brow ridge)
• Proto-Hominins

  • 7 - 4 mya
  • Sahelanthropus
  • Orrorin
  • Ardipithecus
• Australopithecines

  • East & South Africa ( 4.2 -1.1 mya)
  • 10 species in 3 genra
  • overall chimp size
• Gracile


  Older and more ancestral specifically of mandible, maxilla, post-canine dentition and masticatory muscles
• Masticatory muscle


  Masticatory systems muscle that helps chewing, speaking and swallowing located approximately temporal and upper mandible
• Robust


  More recent and more derived specifically of mabdible, maxilla, post canine dentition and masticatory muscles
• Australopithecus anamensis

  • Kenya & Ethiopia (4.2 - 3.8 mya)
  • Primative traits ( Small brains, Prognathic face, climbing wrist & hands)
  • Derived Traits (thicker enamel, maybe bipedalsim )
• Australopithecus Afarensis

  • Ethiopia, Kenya and Tanzania ( 3.9 - 2.8 mya)
  • Laetoli footprints
  • Forests, open woodland and savanah
  • Primative traits ( small brains prognathic face, sexual dimorphism, larger post canine teeth, longer arms)
  • Derived traits ( inefficient bipedal ( short wide pelvis, bigger knee joints) )
• Australopithecus Africanus

  • Lime stones cave in S Africa ( 3.2 - 2.0 mya)
  • Woodland, Savannah, grass land
  • Very similar to Australopithecus afarensis (but small canines, slightly larger brains and longer arms)
• Kenyanthropus Platyops

  • Kenya (3.5 - 3.2 mya )
  • very little material
  • Small post canine teeth
  • thick enamel
  • small brain
  • large, flat face
  • maybe made & used tools
• Genus Paranthropus

  • Eastern & Southern Africa (2.7 - 1.0 mya )
  • Specialized anatomy for eating tough gritty food
  • Megadont
  • well developed sagittal crests & Zygomatic bones/arches
• Megadontia


  Massive post canine teeth with hyper thick enamel
• Sagittal Crest


  ridge along mid line of skull from strong temporalis muscles indicating exceptionally strong jaw muscles
• Paranthropus Aethiopicus

  • Tanzania, Kenya, Ethiopia (2.7 - 2.3 mya)
  • Smaller brains
  • Most Primitive morphology of robust species
• Paranthropus Boisei

  • Tanzania, Kenya, Ethiopia, Malawi (2.4 - 1.4 mya)
  • Most derived and robust of robust species
  • Huge post canine teeth
  • Possible made and used tools
  • Small brains but larger then P. Aethiopicus
• Paranthropus Robustus

  • South Africa (2.3 -1 mya)
  • Most generalized features of robust species
  • Larger Brains (475 - 530cc)