Download Human Evolution - MStew

Human Evolution
Darwin to the Paleolithic
Today’s Objectives
How do humans differ from early primates?
Skeleton, organs, culture
Why was Homo erectus so successful as an early
hominid?
What happened to Neanderthals?
Be able to briefly trace the cultural development
of:
tools, fire, clothing, shelter, art
What is so important about the Upper
Paleolithic?
Theories of Evolution
Origin Myths/Cosmologies
Greek – Prometheus
Genesis
**Above both Western Examples
Left: Prometheus and Athena
Top: God and Adam
Theory 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
The Theory of Evolution
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
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 - 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
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)
Pre-hominid Evolution
Ardipithecus ramidus 4.4 - ? Mya (million years ago)
A. anamensis 4.2 - 3.9
A. afarensis 4.2 - 2.5
A. bahrelghazali 3.5 - 3.0
A. africanus 3.5 - 2.5
P. aethiopicus 2.7 - 2.3
A. garhi 2.5 - ?
P. boisei 2.3 - 1.3
P. robustus
Bipedalism
Tools
Language
2.0 - 1.0
Reconstruction of Australopithecine
Hominid
Evolution
Homo habilis (2.0 – 1.6mya)
H. rudolfensis (2.4-1.6mya)
H. erectus (1.9-27kyBP)
H. heidelbergensis (800-100kyBP)
H. neanderthalensis (300-30kyBP)
H. sapiens (130kyBP – present)
Hominid
Evolution
Major Homo advances:
Brain size
Better bipedalism
Hunting
Fire (H. erectus)
Tools
Oldowon (H. habilis)
Acheulean (H. erectus)
Mousterian (H.
heidelbergensis)
Solutrean (H. sapiens)
Built shelters (H.
heidelbergensis)
Clothing (H.
neandertalensis)
Language (Neanderhtals?)
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 neanderthalansis
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.
Neanderthal
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
Neanderthals?
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
Archaic H. sapiens Culture
rchaic H. sapiens Culture
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 –
40 – 10k yBP
Hotbed of Culture
Shelters
15,000 yBP Ukraine
Top: Straw Hut
Some made with mammoth bones
Wood, leather working; carpentry
Left: Mammoth bone
hut
Tools
From cores to blades
Specialization
Composite tools
Bow and arrow
Domestication of dogs
Gathering rather than hunting became the
mainstay of human economies.
Bottom: Tool
progression
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
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
Top: Straw Hut
Left: Mammoth bone
hut
From cores to blades
Specialization
Composite tools
Bow and arrow
Domestication of dogs
Gathering rather than hunting became
the mainstay of human economies.
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