Evolution

1. What Makes us Human?
Who are our nearest
relatives in the animal
kingdom?
When did our human
features first appear in
the course of human
evolution?
What impacts did these human features
have on human behavior, cultural
development, and movement
geographically?

3. What is a Hominid?
Bipedalism
|
Arboreal Arms
|
Teeth

4. Hominid Taxonomy Linnaean Taxonomy
binomial nomenclature
Most specific
Most general
Homo, Australopithecus
sapiens, neanderthalensis, afarensis
Hominidae (Great Apes: chimps, humans, gorillas, orangutans)
Primates: Descent from same primate??? Missing link?
Mammalia
Vertabrata
Here’s the proper way to write taxa:
Homo sapiens or H. sapiens
Australopithecus afarensis or A. afarensis

5. Chimps vs. Humans
modern humans (Homo sapiens)
Physical
•bipedal large cranial capacity, ca.
1325 cc
•vocal tract with large phonetic range
• small canines (both sexes)
•thick tooth enamel
•long lumbar region (5 vertebrae)
•precision and power grips - both good
• relatively hairless
•estrus cycle unpronounced
•menopause in older females
Behavioral
•“abstract” intelligence (symbolic
thought)
•complex symbolic language
• tool use and tool making - very
complex ( fire, clothing, composite
tools, etc.)
•food sharing
•home bases and central place
foraging
•division of labor
•long learning periods for offspring
•complex cultural behaviors
modern chimps (Pan troglodytes)
Physical
•quadrupedal small cranial capacity, ca.
425 cc
•vocal tract with limited phonetic range
• dimorphic canines - larger in males
• thin tooth enamel short lumbar region
(3 vertebrae)
• precision grip (poorer), power grip
(good)
•relatively hairy
•estrus cycle pronounced
• no menopause in older females
Behavioral
•less “abstract” intelligence
•less complex communication system
•very simple tool use and tool making
•no delayed food consumption
•minimal food sharing
•lack home bases
•central place foraging lacks division of
labor
•shorter learning periods for offspring
•simple cultural behaviors
HOW ARE WE
ALIKE?
HOW ARE WE
DIFFERENT?
(How do we
maintain balance)

7. Apes vs. Hominids
modern humans (Homo sapiens)
Physical
•bipedal large cranial capacity, ca.
1325 cc
•vocal tract with large phonetic range
• small canines (both sexes)
•thick tooth enamel
•long lumbar region (5 vertebrae)
•precision and power grips - both good
• relatively hairless
•estrus cycle unpronounced
•menopause in older females
Behavioral
•“abstract” intelligence (symbolic
thought)
•complex symbolic language
• tool use and tool making - very
complex ( fire, clothing, composite
tools, etc.)
•food sharing
•home bases and central place
foraging
•division of labor
•long learning periods for offspring
•complex cultural behaviors
modern chimps (Pan troglodytes)
Physical
•quadrupedal small cranial capacity, ca.
425 cc
•vocal tract with limited phonetic range
• dimorphic canines - larger in males
• thin tooth enamel short lumbar region
(3 vertebrae)
• precision grip (poorer), power grip
(good)
•relatively hairy
•estrus cycle pronounced
• no menopause in older females
Behavioral
•less “abstract” intelligence
•less complex communication system
•very simple tool use and tool making
•no delayed food consumption
•minimal food sharing
•lack home bases
•central place foraging lacks division of
labor
•shorter learning periods for offspring
•simple cultural behaviors
HOW ARE WE
ALIKE?
HOW ARE WE
DIFFERENT?
(Hint: How do we
maintain balance)

10. Human Evolution: Figuring it Out
7 Key Species
Australopithecus afarensis
A. africanus
A. robustus
Homo habilis
H. erectus
H. neanderthalensis
H. sapiens

12. genus: Australopithecus
Gracile vs. Robust
afarensis:
•3.2 to 2.9 million years old
•1 to 1.2 meters tall
•brain size = 400-500 cc
• generally ape-like face
•Where: Africa only (east)
•Primitive Characteristics:
include long arms, short
legs, and curved finger and
toe bones
•Human Characteristics:
include hind limbs and
pelvis fully adapted for a
type of bipedal locomotion
• LUCY – Hadar - Laetoli
africanus:
•3.3 to 2.5 million years ago
•brain size = 400-500 cc
•Where: Africa only (southern)
•a more globular cranium and
slightly higher ratio of brain size
to body size than afarensis
(evolved from afarensis?)
•anterior pillars, which are
located on either side of the nose
(evolutionary link to robustus?)
•More human-like cranium and
larger brain than afarensis
•Still not 100% sure how this
relates to human ancestry
•Sterkfontein – Taung baby
robustus:
•2.0-1.0 million years ago
•Brain size: 410-530 cc
•Build: Very heavy build; relatively long arms
•Where: Africa only (southern)
•Skull: Sagittal crest on top of skull; long, wide,
flatter face; moderate facial buttressing, broad
cheekbones
•Jaws: Very thick jaws; small incisors and
canines; large, molar-like premolars; very large
molars
•Swartkrans - Dreimulen, and Kromdraai –
Sterkfontein?

13. genus: Homo
What makes Australopithicene different from Homo?
Image: L. Meszoly, Harvard U.

14. Australopithecine or Homo??????
Drawing Genus Boundaries
Wood and Collard suggest that a fossil species should be included in genus Homo
only if most of the following criteria can be demonstrated:
1. The species is more closely related to H. sapiens than it is to the
australopithecines
2. The species has an estimated body mass more similar to that of H. sapiens
than to that of the australopithecines
3. The species has reconstructed body proportions that match those of H.
sapiens more closely than those of the australopithecines
4. The species has a postcranial skeleton whose functional morphology is
consistent with modern human-like bipedalism and limited facility for climbing
5. The species is equipped with teeth and jaws that are more similar in terms of
relative size to those of modern humans than to those of the australopithecines
6. The species shows evidence for a modern human-like extended period of
childhood growth and development.

15. genus: Homo
•2.5-1.6 million years ago (in existence for 400,000 years)
•Brain size: highly variable from 500-800cc.
•Where: Throughout Africa
•First evidence of stone tool production and usage. (Sterkfontein)
•Sites: Sterkfontein, and Great Rift Valley: Omo, Hadar (Ethiopia), Olduvai Gorge
(Tanz), Koobi Fora (Kenya)
•Fossil remains are very poor. Uknown whether evolved from A. africanus or A.
afarensis.
Homo habilis – “The Handy Man”

16. genus: Homo
Homo erectus - “Upright Man”
•1.8 million – 400,000 years ago
•Brain size: 780-1225 cc (about 75% of H. sapien brain size)
•Where: Throughout Africa, China, Java
•Average height: 1.79m = 5’10’’
•Skull: forehead less sloping and teeth smaller than H. habilis
•Tools: more sophisticated stone tool technology, from Oldowan to Acheulean (bifacial)
•First use of controlled fire ~ 790,000 years ago
•First hunter-gatherer society, infrequent group hunting
•Crude shelters, possibility for language usage
•Evidence of migration
•Sites: Lake Turkana (Kenya), Choukuotien – Peking Man (China), Java Man (Indonesia)

17. genus: Homo
Homo neanderthalensis: “Neanderthals”
•250,000 – 24,000 years ago
•Coexistence with H. erectus and H. sapiens. Are we related to Neanderthals? What happened to them?
•Brain capacity: 1200-1750 cc – larger than Homo sapiens!
•Average male height: 1.65 m tall (5' 5") ; Average female height: 1.53 to 1.57 m tall (5'–5'2").
•Skeletal differences: larger cranium, elongated skull, short but robust builds, and large noses — traits selected by
nature in cold climates. Occipital bun. Hyoid bone.
•Where: Europe and western Asia
•Stone tool technology: Mousterian, characterized by Levallois technique (soft hammer percussion)
•whether modern man evolved from this hominid -- or was the Neanderthal a separate branch that became
extinct?
•Burial of dead, personal adornment, clothing, simple language, ritual behavior, use of symbols
•Sites: Shanidar Cave (Iraq) flower burials – 60,000 years old, Kebara Cave (Israel) – 60,000 y.o., La Ferassie
(France) oldest / most complete skeletons – 72,000 y.o.

18. genus: Homo
Homo sapiens: Us!
• From ~250,000 years ago – present
•Brain capacity: 1000-1850cc
•Average height: 1.4-1.9m
•Worldwide
•Complex societies, elaborate architecture, kinship structures, shared resources, rituals,
complex language

19. How are we related?? Hominid Family Tree(s)
Warning!!
It’s dangerous to draw lines where the record’s very
incomplete. Some species are still represented by very
few fossils. Instead paleoanthropologists must look for
patterns of evolution in the fossil remains.

20. Where do we come from? Hominids on the Move
2 Migration Models: Did Homo sapiens evolve in Africa or in various
places around the world?
Out of Africa
Multi-regional Model

21. What exactly evolved? And why are these features so
important? A summary…
Cranial Capacity | Brain Size

22. What exactly evolved? A summary…
TEETH
Chimp
Modern homo sapiens
Homo erectus
A. africanus

23. What exactly evolved? A summary…
Skeletal Features, including:

24. What exactly evolved? A summary…
BIPEDALISM: SPINAL COLUMN

25. BIPEDALISM: LIMBS and SKELETAL CHANGES
What exactly evolved? A summary…
Laetoli footprint