Hominin Evolution

1
Hominin Evolution
2
Pre-dating Australopithecus

• Hominins discovered in north-central and eastern
  Africa
• Bipedal debatable in some species
• We will focus on the species for which there is
  stronger evidence of bipedalism

3
Ardipithecus ramidus

• Middle Awash area of Ethiopia
• Approximately 4.4mya
• Found
• Dental
• Cranial
• Post-cranial remains

4
Ardipithecus ramidus

• Indicators of Bipedalism
• Foramen magnum location
• Femur and pelvis
• Humerus chimp features, but not weight bearing
• Foot Phalanges curved like apes

5
Ardipithecus ramidus
6
Ardipithecus ramidus

• Ardi facultative biped
• What do you think this term mean?

Living in both worlds up in the trees at times
while also on the ground
7
Australopithecus afarensis

• East Africa
• Hadar, Ethiopia
• Laetoli, Tanzania
• 3.6-3.0 mya
• Forest, woodland, grassland

8
A. afarensis Traits

• Bipedal
• Vertical foramen magnum
• Heel-knee joint human-like
• Some Arboreal Abilities Retained
• Curved phalanges
• Long arms for body size

9
Type Fossil Lucy

• Found 1974, Hadar, Ethiopia
• 40 complete skeleton
• Both arms
• Much of the pelvis
• Left femur, right tibia
• Hand and Foot bones
• Adult (based on 3rd molar)
• Female?

10
Type Site Laetoli Footprints

• Tanzania
• 3.6 mya
• 75 feet long preserved
• Walked over volcanic ash, rained, hardened
• 3 hominins
• 2 adults, 1 child

11
A New Hominin

• Australopithecus sediba
• Discovered in 2008 located in South Africa
• Proposed by some to be the best candidate
  ancestor for the genus Homo

12
A New Hominin

• Features
• Small brain
• Pelvis mixture of Australopithecus-like and
  Homo-like features
• Hand combination of ape- human-like
• Foot ankle shape combination of ape-
  human-like

13
The Genus Homo Overall Trends

• Characterized by
• Increased brain size
• Increased body size
• Diet expands
• Meat incorporation
• Reliance on material culture
• Stone tool use
• Fire and cooking

14
Introduction To Homo habilis

• Contemporaneous with australopithecine remains
• Anatomically different than specimens assigned to
  the genus Australopithecus
• Distinguishing feature cranial size
• H. habilis shows an increase in cranial size as
  compared to Australopithecines

15
Homo habilis OH 24

• Location Olduvia Gorge
• Comparison to Australopithecines
• Larger brain
• Less protruding face

Twiggy or OH 24 Dated to 1.8mya