Mary Leakey &Louis Leakey
(English/Kenyon Anthropologist) husband and wife team that conducted the earliest excavations on geologic strata at Olduvai Gorge, a side branch of the Rift Valley,1959
laying the essential groundwork for our present understanding of the first
humans and
Leakey's discovery of human skull in Olduvai Gorge in 1959
discovery expanded the territory in which early hominins were known to have lived (at that point, they were known just from South Africa)
added a whole new dimension to their variability and geographical distribution.
Larsen, Clark Spencer (2014-02-01). O
Speech, advanced cognition, and complex material culture evolved in the human line long after the first hominins appeared in Africa in ________
7-6 MYA
speech 2 million
material culture 2.6
therefor these traits do not define a hominin, only evolved in humans in addition to large brains
Since 1800's, the large fossil record has proven that _____________, is the foundational behavior of the Hominini
bipeadalsim, NOT intellegence
(speech, intelligence, and material culture occurring millions of years later)
Australopithecus boisei, fossil OH 5
one of the most famous ever recovered from Olduvai Gorge. The almost complete cranium is of an adult male. Its robust features and large molars caused
anthropologists to classify it as a robust australopithecine.
Seven skeletal characteristics that distinguish primate skeleton
1. the foramen magnum is positioned on the bottom of the skull
2. the spine is S-shaped
3. the ilium is short from front to back
4. the legs are long relative to the body trunk
5. arms the knees are angled inward
6. the foot has a longitudinal arch
7. the
Seven steps of bipedalism: Position of the foramen magnum
In humans, the foramen magnum is on the bottom of the skull, closer to the teeth. In apes, the foramen magnum is in a posterior position. This difference reflects the fact that the human head sits on top of the body trunk, whereas the ape head sits on the
Seven steps of bipedalism: Shape of the spine
In humans, the spine has an S-shape. In apes, it is straighter, almost C-shaped. The distinctive S-shape in humans is created by the
concave curvature of the thoracic vertebrae, in front, and the concave curvature of the lumbar vertebrae, in the back. Thi
Seven steps of bipedalism: Shape of the pelvis
the human pelvis has a very different shape from the ape pelvis. Especially distinctive is the short ilium in the bipedal human. This morphology is an essential element of the stability of the pelvis during standing, walking, and running
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Seven steps of bipedalism: Length of the leg
The relatively long leg of the bipedal human provides increased efficiency during stride. In hominins, the leg is generally longer relative to the arm than it is in apes. The long arm of the ape reflects its suspensory use in trees.
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Seven steps of bipedalism: Valgus knee
The knees in the biped angle inward to give it a knock-kneed appearance. The angle formed by the long axis of the femur shaft and the horizontal at the knee�called the bicondylar angle�provides an angle greater than 90 degrees. This angle is significantly
Seven steps of bipedalism: Longitudinal foot arch:
The biped has a distinctive arch that runs from the front to the back of the bottom surface of the foot. This form gives increased
leverage as the body pushes forward and serves as a shock absorber when the feet make contact with the ground during walking
Seven steps of bipedalism: Opposable big toe
The first digit of the foot�the big toe�is opposable in apes but not in humans. This difference reflects the function of the foot, which
is solely (pun intended!) to support the body during walking and running in humans. The ape toe has a dual function, i
The two major differences between living humans and apes
bipeadalsim- the seven differences in the skeletal structure that makes bipedalism possible
the way the dentition processes food
Characteristic that defines the Homininae
the way the dentition processes food
Characteristics of Ape's upper canine
become large, pointed, and projecting, with a sharp edge on the back
292
Anatomical characteristics of nonhoning canine behavior
Blunt, non-projecting canine
Small canine relative to size of other teeth
No diastema
Wear on tips of canines and of third premolars
Cusps on lower third premolar equal size
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Anatomical characteristics of bipedalism behavior
Foramen magnum on the bottom of the skull
S-shaped spine
Short pelvis from front to back
Long legs
Knees angled toward midline of the body
Double-arched foot, including a well-developed
longitudinal arch
Nonopposable big toe
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When did Hominins emerge
late Miocene epoch, some 5.3-10 mya.
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Darwin's hypothesis on origin of Humans
Darwin concluded that because of the remarkable anatomical similarity between humans and African apes, Africa was hominins' likely place of origin, influence by Thomas Huxley's work
Larsen, Clark Spencer (2014-02-01). Our Origins: Discovering Physical Ant
Darwin's hunting hypothesis
canine reduction began with tool use
bipedalism had freed the hands for carrying the weapons. To manufacture and use these tools, the early humans needed great intelligence. Once they had the tools, they did not need the big canines for hunting or for def
Facts that disproved Darwin's hypothesis
Scientists now know that tool use (2.6 MYA) and the increase in brain size, began well after the appearance of bipedalism and the reduction in canine size
Larsen, Clark Spencer (2014-02-01). Our Origins: Discovering Physical Anthropology (Third Edition) (
Darwin's 4 observations of primates that lead to his hunting hypothesis
(1) humans are bipedal, while apes are quadrupedal; (2) humans have tiny canines, while apes have large canines; (3) humans rely on tools in their adaptation, while apes do not; and (4) humans have big brains, while apes have small brains
Larsen, Clark Sp
The earliest hominins were known from one genus, Australopithecus, found mostly in two key areas of Africa:
in a series of limestone caves in South Africa and in sedimentary basins and associated river drainages in the Eastern Rift Valley (part of the Great Rift Valley) in Ethiopia, Kenya, and Tanzania
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pre-australopithecines represent
the first recognizable ancestors of the lineage leading to humans.
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Micheal Brunet
French Paleontologist who found earliest pre-australopithecine skull in the Toros-Menalla locality of the Djurab Desert, Chad named species Sahelanthropus tchadensis, dates 7-6 MYA
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Geographic windows of early hominins
central, east, south Africa
Discovery of sahelanthropus tchadensis was geographically significant because
opened a new window of location of early hominins, which was now in central Africa, 2,500 km away from Eastern Rift Valley (east/south Africa) where all fossils had been found
Sahelanthropus tchadensis
The earliest pre-australopithecine species found in central Africa with possible evidence of bipedalism.
7-6 MYA, Toros-Menalla in Djurab Desert,Chad
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Orrorin tugenensis
A preaustralopithecine species found in East Africa that displayed some of the earliest evidence of bipedalism.
6 MYA, Tugen Hills,Kenya's Lake Turkana
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