1. What Traits Characterize Humans?
Bipedal Locomotion
Involves modifications of pelvis, femur, and backbone
Various hypotheses regarding benefits, including free hands (vs. knuckle- walking and brachiation of great apes)
Large Brain Size
Requires omega fatty acids – high levels in marine organisms, nuts, marrow
The Making and Use of Complex Tools
Earliest stone tools produced by chipping flakes from a rock; oldest dated at ~ 2.5 mya (Oldowan Stone Tools)
Opposable thumbs allow fine control and tight grips; include thick meta- carpals with broad heads for muscle attachment; three muscles not found in chimpanzees
Language and Cultural Evolution
Capacity for language is innate in humans (ex., children born deaf create languages)
Modifications of larynx allow more tongue movement and great diversity of vocalizations (trade-off is greater chance of choking); hyoid bone of Neanderthals virtually identical to that of present-day humans
Memes: ideas that can be disseminated via oral or written means, subject to modifications and non-genetic descent (impart information, cultural analogue to genes)

2. Fig. 34-37 Lemurs, lorises, and pottos New World monkeys Anthropoids
ANCESTRAL
PRIMATE
Tarsiers
New World monkeys
Anthropoids
Old World monkeys
Gibbons
Orangutans
Gorillas
Chimpanzees
and bonobos
Humans 60 50 40 30 20 10
Time (millions of years ago)

3. What are Some Notable Fossil Hominids?
Pre-australopithecine: ~ million years ago (mya)
Sahelanthropus tchadensis: 6-7 mya (Chad); found in lake deposits from ancient Lake Chad
Orrorin tugenensis: ~ 6 mya (Kenya); recent evidence for bipedalism based on CT scan of femur neck (controversial)
Australopithecines: projecting faces; braincases < 550 cm3
Australopithecus africanus: ~ mya; first hominid fossil found in Africa (“Taung Child”); discovered in coastal South African cave by Raymond Dart in 1925; more specimens found nearby in 1930s s
Australopithecus afarensis (incl. “Lucy”): ~ mya (Tanzania and Kenya); footprints in volcanic ash dated at 3.6 mya
Early Humans: apparently coexisted with robust australo- pithecines in Africa
Homo erectus (= H. ergaster): ~ mya; widespread through Africa and Asia (ex. “Java man”); large braincase (> 850 cm3); most likely ancestor of more modern humans
Homo neanderthalensis: ~ mya; found in Europe
Early Homo sapiens (incl. Cro-Magnon): ~ 0.1 mya - present; present-day average braincase = 1200 cm3; Cro-Magnon Man (30,000 ya) buried with animal bones, jewelry, and tools

4. Fig. 34-40 Paranthropus robustus Homo neanderthalensis Homo sapiens
Paranthropus
boisei
Homo
ergaster ?
0.5
1.0
1.5
Australopithecus
africanus
2.0
Kenyanthropus
platyops
2.5
Australo-
pithecus
anamensis
Australopithecus
garhi
Homo
erectus
3.0
Millions of years ago
3.5
Homo
habilis
Homo
rudolfensis
4.0
4.5
Ardipithecus
ramidus
Australopithecus
afarensis
5.0
5.5
Orrorin tugenensis
6.0
6.5
Sahelanthropus
tchadensis
7.0

5. Fig. 34-41 (a) Australopithecus (b) The Laetoli footprints
afarensis skeleton
(b) The Laetoli footprints
(c) An artist’s reconstruction of what A. afarensis may have looked like