Transcript Document

Chapter 2 –
Human Evolution
Today’s Objectives
How do humans differ from apes?
Skeleton, organs, culture
Why was Homo erectus so successful as an
early hominid?
What happened to Neandertals?
Be able to briefly trace the cultural
development of:
tools, fire, clothing, shelter, art
What is so important about the Upper
Palaeolithic?
Theories of Evolution
Origin Myths/Cosmologies
Greek – Prometheus
Genesis
Western examples
Left: Prometheus and Athena
Top: God and Adam
Carl Sagan’s Universe Calendar
24 days = 1 billion years
1 second = 475 years
“Big Bang”
Milky Way
Solar System
Life on Earth
Humanlike Primates
January 1
May 1
September 9
September 25
Milky Way
December 31, 10:30pm
Theories of Evolution
Darwin and Wallace, 1850s
Evolution theory holds that
existing species of plants and
animals have emerged over
millions of years from simple
organisms.
Darwin, On the origin of
species, 1859
Influenced by the principle of
uniformitarianism
Charles Darwin
Theories of Evolution - Corollaries
Darwin’s principle of natural selection
“Natural selection is the gradual process by which nature
selects the forms most fit to survive and reproduce in a
given environment.”
For natural selection to work on a given population, there
must be variety within that population and competition for
strategic resources.
The concept of natural selection argues that organisms
which have a better fit within their environmental niche will
reproduce more frequently than those organisms that fit less
well.
Theories of Evolution - Corollaries
Random genetic drift is the loss of alleles from a
population's gene pool through chance.
Mutation introduces genetic variation into a
breeding population.
Gene flow occurs through interbreeding: the
transmission of genetic material from one population
to another. Gene flow decreases differences and
inhibits speciation, the formation of new species.
Theories of Evolution - Corollaries
Mendel’s principle of inheritance, 1856
The science of genetics explains the origin of the
variety upon which natural selection operates.
By experimenting with successive generations of
pea plants, Mendel came to the conclusion that
heredity is determined by discrete particles, the
effects of which may disappear in one generation,
and reappear in the next.
Other Theories
Creationism accounts for biological diversity by referring to
the divine act of Creation as described in Genesis.
Catastrophism is a modified version of Creationism, which
accounts for the fossil record by positing divinely authored
worldwide disasters that wiped out the creatures represented in
the fossil record, who were then supplanted by newer, created
species.
Intelligent Design states that modern physics and cosmology
have uncovered evidence for intelligence in the structure of the
universe and this intelligence seems to act with us in mind and
that the universe as a whole shows evidence of design.
Early Primates
Prosimians (65mya)
Monkeys (35mya)
Apes (23mya)
Hominids (5mya)
Early Primates - Traits
Common physical primate traits:
Dense hair or fur covering
Warm-blooded
Live young
Suckle
Infant dependence
Common social primate traits:
Social life
Play
Observation and imitation
Pecking order
Common Primate Traits
Primate Family Tree
Crown lemur
Orangutan
Evolution of Bipedalism
Anatomical changes
Neck (1), chest (2), lower back (3), hips and pelvis
(4), thighs (5), knees (6), feet (7)
Theories
Tool use and bipedalism (Darwin/Washburn)
Energy efficiency and bipedalism (Isbell/Young)
Radiator theory (Falk)
Body temperature and bipedalism (Wheeler)
Habitat variability and bipedalism (Potts)
Reproduction and bipedalism (Lovejoy)
Canine reduction and bipedalism (Jolly)
(Click for interactive skeleton)
Pre-hominid Evolution
Ardipithecus ramidus
A. anamensis
A. afarensis
A. bahrelghazali
A. africanus
P. aethiopicus
A. garhi
P. boisei
P. robustus
Bipedalism
Tools
Language
4.4 - ?
mya
4.2 - 3.9
4.2 - 2.5
3.5 - 3.0
3.5 - 2.5
2.7 - 2.3
2.5 - ?
2.3 - 1.3
2.0 - 1.0
Reconstruction of Australopithecine
Hominid Evolution
Homo habilis (2.0 – 1.6mya)
H. erectus
(1.9-27kyBP)
H. heidelbergensis (800-100kyBP)
H. neanderthalensis (300-30kyBP)
H. sapiens
(130kyBP – present)
Scale: Millions of Years BP
H. rudolfensis (2.4-1.6mya)
Hominid Evolution
Major Homo advances:
Brain size
Better bipedalism
Hunting
Fire (H. erectus)
Tools
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Oldowon (H. habilis)
Acheulean (H. erectus)
Mousterian (H. heidelbergensis)
Solutrean (H. sapiens)
Built shelters (H. heidelbergensis)
Clothing (H. neandertalensis)
Language (Neandertals?)
Homo habilis
612 cc brain
2.3 - 1.6 mya
first toolmaker
prognathic face, brow ridge
probable meat-eater
possibly arboreal
discovered in 1960 by Leakeys
no speech
Artist’s representation of a Homo
habilis band as it might have
existed two million years ago.
H. habilis v. H. erectus
Finds in east Africa indicate that Homo habilis
was not very different from the
australopithecines in terms of body size and
shape.
The earliest Homo erectus remains indicate
rapid biological change.
The fossil record for the transition from H. habilis
to H. erectus supports the punctuated equilibrium
model of evolution.
H. erectus was considerably taller and had a larger
brain than H. habilis.
Homo erectus
1891 - Eugene Dubois
discovers H. erectus in Java
Dubois calls it Pithecanthropus
erectus initially, also dubbed
“Java Man”
finds in China called
Sinanthropus
dates from 1.9 mya to 27,000
years B.P.
994 cc brain size (compare to
612 for H. habilis)
Acheulean tool industry
Photograph of Nariokotome boy, an
early Homo erectus found near Lake
Turkana, Kenya.
Homo erectus – 1.9mya to 27k yBP
Why was H. erectus so successful?
Less sexual dimorphism = possible pair bonds, marriage
Less hair on body = wearing of furs, other clothing
Wearing of furs = ability to live further north
Quick adaptation to
environment without physical
changes
Culture is main reason H.
erectus was so successful
• organization for hunting
• ability to protect against
predators
• control of fire?
• possible campsites
• tools (Acheulean industry)
Distribution of H. erectus
Homo neanderthalensis
discovered in the Neander Valley
(Tal) near Dusseldorf, 1856
massive brain--about 1,400cc on
average
large torso, short limbs, broad
nasal passages
later remains show decrease in
robustness of the front teeth and
face, suggesting use of tools
replaced teeth
retained occipital torus, some
mid-facial prognathism
The skull of the classic Neandertal
found in 1908 at La Chapelle-auxSaints.
Neandertal Culture
Homesites – In caves, also in the
open (near rivers, framed with
wood and covered with skins)
Burial – Is there evidence of
purposeful burial and ritual?
Language – Could Neandertals
talk or not?
Tools – Mousterian tradition
Top: Reconstruction of Neandertal burial from Shanidar cave
Bottom: Mousterian tools
What happened to Neandertals?
H. neanderthalensis coexisted with H. sapiens for at
least 20,000 years, perhaps as long as 60,000 years
What happened?
Neandertals interbred with H. sapiens
Neandertals were killed off by H. sapiens
H. sapiens drove Neandertals into extinction by
competition
Homo sapiens
Archaic – 100,000 to
35,000 years BP
Sometimes called Homo
sapiens and Homo
sapiens neanderthalensis
Modern – 35,000 years
BP to present
Anatomically modern
Sometimes called Homo
sapiens sapiens
Cro-Magnon Man
Cro-Magnon humans
35,000 years B.P. in western
Europe to 17,000 years B.P.
1,600 cc cranial capacity
Name comes from a hotel in
France
Not a different species, just old
Homo sapiens from Europe
Artist’s reconstruction of a Cro-Magnon man
Archaic H. sapiens Culture
Art
Traces of art found in beads, carvings, and
paintings
Cave paintings in Spain and southern
France showed a marked degree of skill
Female figurines
27,000 to 22,000 years B.P.
Called “venuses,” these figurines depicted
women with large breasts and broad hips
• Perhaps it was an example of an ideal
type, or perhaps an expression of a
desire for fertility
Archaic H. sapiens Culture
Cave paintings from 20,000 years ago at VallonPont-d’Arc in southern France (left) and from
Lascaux, in southwest France
Cave paintings
Mostly animals on bare walls
Subjects were animals favored for their
meat and skins
Human figures were rarely drawn due to
taboos and fears that it would somehow
harm others
Upper Palaeolithic –
Hotbed of Culture
40 – 10k yBP
Shelters
15,000 yBP Ukraine
Some made with mammoth bones
Wood, leather working; carpentry
Tools
From cores to blades
Specialization
Composite tools
Bow and arrow
Domestication of dogs
Gathering rather than hunting
became the mainstay of human
economies.
Top: Straw Hut
Left: Mammoth bone
hut
Bottom: Tool
progression
Modern Homo Sapiens
Regional-Continuity Model (Milford Wolpoff, UMich)
Humans evolved more or less simultaneously across the entire Old
World from several ancestral populations.
Rapid-Replacement Model (Chris Stringer, NHM London)
Humans evolved only once--in Africa from H. heidelbergensis
ancestors--and then migrated throughout the Old World,
replacing their
archaic
predecessors.
Also called the
“Out of Africa”
and “Killer Ape”
hypothesis.
Social Organization
Hunter-gatherer analogy
Small group, low population density, nomadism,
kinship groups
Migration
North America was the last colonized by hominids.
Beringia (land bridge) between Russia and Alaska
Asian origin of Native Americans
30,000 to 12,000 years B.P. was first migration
Human Variation
Modern humans vary in skin color, hair
color, and eye color.
Will talk about anthropological
conceptions of race and ethnicity later
in the semester (April 23).