Human Evolution
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Human Evolution
Today’s Objectives
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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?
Slide 3:
Classification Hierarchy Kingdom Animalia Phylum Chordate Class
Mammal Order Primates Family Hominids Genus Homo Species Sapiens
Theories of Evolution
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Theories of Evolution Origin Myths/Cosmologies Greek – Prometheus
Genesis Left: Prometheus and Athena Top: God and Adam
Theories of Evolution
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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 :
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 :
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.
Other Theories
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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
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Early Primates Prosimians (65mya) Monkeys (35mya) Apes (23mya)
Hominids (5mya)
Early Primates -
Traits :
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
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Primate Family Tree
Slide 12:
Evolution of Primates The evolution of primates is characterized
by trends towards: mobile limbs grasping hands (with opposable thumbs) a
flattened face binocular vision a large, complex brain (for learned behavior) a
reduced reproductive rate
Slide 13:
Mobile Limbs Most primates have flat nails as well as sensitive
pads on the undersides of fingers and toes. Many also have both an opposable
big toe and thumb. Mobile limbs and clawless opposable digits allow primates to
freely grasp and release tree limbs.
Slide 14:
Primate Hands
Slide 15:
Evolution of Primates (cont..) Prosimians were the first type of
primate to diverge from the ancestral primate line. Surviving anthropoids are
classified into three superfamilies. New World monkeys Old World monkeys
Hominoids
Slide 16:
Primate Bone structure
Evolution of
Bipedalism :
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)
Hominid Evolution
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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 (Neandertals?)
Slide 19:
Hominoid Evolution Proconsul is believed ancestral to hominids.
Slide 21:
Evolution of Hominids Phylogenetic tree indicates humans are most
closely related to African apes. Last common ancestor appears to have lived
about 5-7 million years ago (mya) Genetic changes used as a molecular clock to
measure relatedness of different groups.
Slide 22:
Hominids To be a hominid, a fossil must have an anatomy suitable
for standing erect and walking on two feet. Bipedalism Human anatomy differs
from that of an ape largely because humans are bipedal while apes are
quadrupedal.
Slide 24:
Australopithecines It is possible that one of the
australopithecines that evolved and diversified in Africa 4 mya is a direct
ancestor of humans. Southern Africa Australopithecus africanus Eastern Africa
Australopithecus afarensis (Lucy)
Slide 25:
A reconstruction of Lucy’s skeleton Lucy is ~
3.5-million-years-old Australopithecus afarensis adaptations in Lucy’s hip, leg
and foot allowed a fully bipedal means of locomotion Lucy
Homo habilis :
Homo habilis Artist’s representation of a Homo habilis band as it
might have existed two million years ago. 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
H. habilis v. H.
erectus :
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 :
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 :
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
Slide 30:
Homo erectus Homo erectus and like fossils are found in Africa,
Asia, and Europe and are dated between 1.9 and 0.3 mya. Larger brain and
flatter face than Homo habilis. Much taller than previous hominids. Believed to
have first appeared in Africa and then migrated into Asia and Europe. First
hominid to use fire.
Slide 31:
Homo erectus Using Tools Re-creation of a Pleistocene setting in
which Homo erectus use fire & stone tools
Slide 32:
Homo erectus1.6 mya bipedal Homo habilis = handy human1.5 to 2 mya
Slide 33:
Evolution of Modern Humans Most researchers believe Homo sapiens
evolved from Homo erectus. Multiregional Continuity Hypothesis Similar
evolution occurred in many different places. Out-of-Africa Hypothesis H.
sapiens evolved from H. erectus only in Africa, and thereafter migrated to
Europe.
Homo neanderthalensis
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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-aux-Saints.
Slide 35:
Neanderthals Neanderthal (H. neanderthalensis) skeletons were
first discovered in Germany’s Neander Valley. Skeletons date back 200,000
years. Massive brow ridges with protruding nose, jaws, and teeth. Heavily
muscled. Culturally advanced. Manufactured variety of tools. Neanderthals
35,000 to 100,000 ya
Slide 36:
Reconstructed Neanderthal skull characterized by prominent heavy
brow ridges and week chin
Slide 37:
Burial Ceremony in a Cave Neanderthals lived in caves and had
ritual burials, such as this depiction from Shanidar Cave, Iraq
Neandertal Culture
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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
Slide 39:
Flaked stones that fit in wood handles. Buried their dead with
spices and bedding. Built sturdy huts. Made flutes! A flute formed from a femur
& 4 remaining holes.
What happened to
Neandertals? :
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 :
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
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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
Slide 43:
Cro-Magnons – Homo sapiens Oldest fossils to be designated H.
sapiens. Modern humans who entered Asia and Europe from Africa 100,000 years
ago. Made advanced stone tools. Accomplished hunters. Hunted cooperatively.
First to have complex language?
Slide 44:
Cro-Magnon 35,000 to 40,000 ya
Archaic H. sapiens
Culture :
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 :
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 Cave
paintings from 20,000 years ago at Vallon-Pont-d’Arc in southern France (left)
and from Lascaux, in southwest France
Slide 47:
Cro-Magnons were very skilled cave painters Painting of a horse
from a cave in France Painting From a Cave in France
Slide 48:
Homo Floresiensis (hobbits) - one meter high - lived in Flores
12,000 yrs ago - Upright posture - 380 cc cranial size (like a chimp)
Upper Palaeolithic –
Hotbed of Culture :
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
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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
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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
Slide 53:
With the appearance of Cro-Magnons, human evolution has become
almost entirely cultural rather than biological Humans have spread throughout
the world by devising means to deal with a broad range of environmental
conditions Cultural Evolution
Slide 54:
THANK YOU!!
