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Unformatted text preview: Early Hominids:
Chapter Three major groups of early
1. Pre-australopiths-earliest and most
primitive possible hominids (7.0-4.4
2. Australopiths-diverse forms, some
more primitive, others more derived.
First definitive hominids. (4.2-1.2 Ma.)
3. Early Homo-the first members of our
genus (2.4-1.4 Ma.)
Australopiths Two closely related genera: Australopithecus (Gracile
australopiths) Paranthropus (Robust
australopiths) Gracile Australopiths (2.5-4.2
Africa) A. afarensis A. africanus Features of Australopiths
3. They are all clearly bipedal (although not necessarily
identical to Homo in this regard).
They all have relatively small brains (i.e., at least
compared to Homo).
They all have large teeth, particularly the back teeth,
with thick to very thick enamel on the molars.
with Australopithecus afarensis
(East Africa) A.L. 288 “Lucy” A. afarensis Primitive Characteristics
Primitive Small Brain
Small Brains a little larger
than Pan: 400-500
cubic centimeters Projecting face
Projecting Chimpanzee, A. afarensis, Human
U-shaped U-shaped Parabolic Flat jaw joint
Flat “Lucy” and H. sapiens female Small stature,
between 3-5 feet.
between Still a tree climber?
Homo Long curved
toes Derived Traits
Derived Primitive traits shared with living
apes Brains 400-500 cubic centimeters (cc) (Ape-like)
Dental arcade U-shaped
Canines larger, more sexually dimorphic than in
Asymmetrical premolars, not strongly bicuspid
Broad cranial base, flat jaw joint
Limb proportions intermediate between
chimpanzees and humans (long arms, short legs)
Long, curved fingers and toes Derived Traits
Derived Canine reduction: canines are intermediate
in size between Pan and Homo
Homo Premolars show slight development of
second Very large cheek teeth, thick enamel: More
grinding, dietary shift towards harder to
process Bipedal (not like a modern human) A. afarensis
A. Modern Human Derived Postcranial Features (Bipedality)
1. Foramen magnum underneath skull
(to balance head on vertebral
2. Vertebrae are wedge-shaped, giving
spine shock-absorbing curves
3. Short, broad pelvis --but lesser
gluteal muscles not wrapped around
hip joint as much as in humans;
pelvis balancing mechanism may not
be fully developed
4. Femur is angled towards midline,
maintains balance over one foot
5. 6. Non-opposable big toe, arches in
foot Laetoli, Tanzania: 3.6 Ma footprints
Laetoli, Arches in the Foot: shock absorption
Australopithecus Human Arch Laetoli footprint A. afarensis males>>females
Male average 4’ 11”, 99 lbs
Female average 3’ 5”, 64 lbs ...
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This note was uploaded on 12/05/2011 for the course ANTHRO 102 taught by Professor F during the Spring '11 term at CUNY Queens.
- Spring '11