Download Homo sapiens

Human Evolution
The Evolutionary Path to Humans Begins
with Early Primates
• The story of human evolution begins around 65 M.Y.A.
• This time marks the explosive radiation of a group of
small, arboreal mammals called the Archonta
 they were likely nocturnal and were arboreal and insectivorous
 their radiation gave rise to different types of mammals, including
• bats, tree shrews, and primates
• primates are the order of mammals that includes humans
The Evolutionary Path to Humans Begins
with Early Primates
• Primates are mammals with two distinctive
features that allowed them to succeed in
the arboreal, insect-eating environment
 grasping fingers and toes
• the first digit in many primates is opposable and at
least some of the digits have nails
 binocular vision
• this permits the brain to judge distance precisely
Origin of Anthropoids
• Anthropoids are higher primates and include
monkeys, apes and humans.
• Almost all diurnal (active during the day).
• Evolution:
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Eye changes;
Larger brains;
Social interactions;
Long-term tending of their young to improve learning
and brain development.
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
The Evolutionary Path to Humans Begins
with Early Primates
• About 40 M.Y.A. the earliest primates split into
two groups
 prosimians
• surviving representatives today include the tarsiers, lemurs,
and lorises
• most are nocturnal
 anthropoids
• these higher primates included monkeys, apes, and humans
• the early anthropoids, now extinct, likely evolved in Africa
Figure 27.1 A primate evolutionary tree
Hominin Diversity: Fossil Sites in the Old World
8
The Evolutionary Path to Humans Begins
with Early Primates
• The monkeys are a very successful group of
primates
 New World monkeys
• South American descendants of African ancestors
• all are arboreal, have flat spreading noses, and prehensile
tails
 Old World monkeys
• descendants of the ancestral anthropoids that remained in
Africa
• none have prehensile tails
• include both ground-dwelling and arboreal species
How the Apes Evolved
• Hominoids evolved from anthropoid
ancestors
 hominoids are comprised of the apes and the
hominids (humans and their direct ancestors)
27.2 How the Apes Evolved
• Studies of ape DNA have revealed much about
how living apes evolved
 Asian apes evolved first
• gibbons diverged from other apes about 15 M.Y.A.
• orangutans split off about 10 M.Y.A.
• neither are closely related to humans
 African apes evolved more recently (between 6 to 10
M.Y.A.)
• these apes are the closest living relatives to humans
27.2 How the Apes Evolved
• Chimpanzees are more closely related to
humans than gorillas are
 chimpanzees diverged from the ape line less than 6
M.Y.A.
 the genes of humans and chimpanzees have not had
time to evolve many differences
• humans and chimpanzees share 98.6% of their nuclear DNA
 gorilla DNA differs from human DNA by about 2.3%
• gorillas split off from the ape line around 8 M.Y.A.
How the Apes Evolved
• The common ancestor of apes and hominids is
thought to have been an arboreal climber
• Much of the subsequent evolution of the
hominoids differs with respect to locomotion
 hominids evolved bipedal walking
• anatomical features include S-shaped spine, bowl-shaped
pelvis, lower limbs larger than upper limbs
 apes evolved knuckle-walking
• anatomical features include slightly curved spine, long pelvis,
upper limbs larger than lower limbs
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)
Figure 27.3 Walking upright has evolved
many times among vertebrates
A comparison of ape and hominid skeletons
The first of our genus: Early Homo
17
Hominin Evolution
• Major Homo advances:
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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?)
27.5 African Origin: Early Homo
• The first humans evolved from australopithecine
ancestors about 2 million years ago
• Homo habilis
 it had a larger brain volume than Australopithecus but
was similarly short in stature
 called “handy man” because of its association with
tools.
Figure 27.6 Homo habilis
Homo habilis
612 cc brain
2.3 - 1.6 mya
first toolmaker
Artist
rendition of
H. habilis.
prognathic face, brow ridge
probable meat-eater
possibly arboreal
discovered in 1960 by Leakeys
ER-1813 –
Homo habilis
Oldowan Tool Industry
The Oldowan is the first known industrial
complex in prehistory. It takes its name from
Olduvai Gorge, Tanzania
Oldowan tool use is estimated to have
begun about 2.5 million years ago (mya),
lasting to as late as 0.5 mya.
It is thought that Oldowan tools were
produced by several species of hominids
ranging from Australopithecus to early
Homo.
• Chopper with simple edge
• Chopping tool
• Unretouched biface
H. habilis vs. 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.
 H. erectus was considerably taller and had a larger brain
than H. habilis.
Figure 27.7 Homo ergaster
27.5 African Origin: Early Homo
• Too few fossils have been found of early Homo
to explain with certainty the evolution of Homo
 if two species are accepted, then it would appear
Homo underwent an adaptive radiation
 because of its modern skeleton, Homo ergaster is
thought to be the most likely ancestor to later species
of Homo and is often lumped with Homo erectus
27.6 Out of Africa: Homo erectus
• Homo erectus is definitely a true human and
has been supported by many specimen finds,
including those of Java Man and Peking Man
• Homo erectus was taller and had a larger brain
than H. habilis
 the shape of the skull interior suggests that it was
able to talk
 it was a social species
Homo (ergaster) erectus
1891 - Eugene Dubois
discovers H. erectus in Java
Dubois calls it Pithecanthropus
erectus initially, also dubbed
“Java Man”
Dates from 1.9 mya to 27,000
years B.P.
994 cc brain size (compare to
612 for H. habilis)
Acheulean tool industry
All finds in E. Asia are H.
erectus, everywhere else is
called H. ergaster.
Photograph of Nariokotome boy,
an early Homo erectus found near
Lake Turkana, Kenya.
Turkana Boy Homo ergaster
Turkana Boy: a nearly
complete skeleton of an 11 or
12 year old boy who died
approximately 1.5 million
years ago near Lake Turkana
in Kenya by Kamoya Kimeu
and Richard Leakey in 1984.
Homo ergaster – 1.9mya to 27k yBP
• Why was H. erectus so successful?
 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
Acheulean Tools
• Acheulean tools are typically
found with Homo erectus
remains.
• It was the dominant technology
for the vast majority of human
history and more than one million
years ago it was Acheulean tool
users who left Africa to first
successfully colonize Eurasia.
Homo neanderthalensis
• discovered in the Neander Valley
(Tal) near Dusseldorf, 1856
• massive brain--about 1,400cc on
average
Range of Homo neanderthalensis
• 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
The skull of the classic
First reconstruction of
Neandertal found in
Neanderthal man.
• retained occipital torus, some
1908 at La Chapelleaux-Saints.
mid-facial prognathism
http://www.youtube.com/watch?v=5OJcS3y3mlI&feature=SeriesPlayList&p=39B8670A9074CF60&index=0
http://www.youtube.com/watch?v=CgEFoY-hoT4&feature=SeriesPlayList&p=39B8670A9074CF60&index=2
http://www.youtube.com/watch?v=pKs1Q7f1Uzg&feature=SeriesPlayList&p=39B8670A9074CF60&index=3
http://www.youtube.com/watch?v=o589CAu73UM&feature=SeriesPlayList&p=39B8670A9074CF60&index=5
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
http://www.youtube.com/watch?v=IsSOcwY79ig&feature=related
Homo sapiens
•
Archaic – 150,000 to 35,000 years BP
 Earliest members of the species Homo
sapiens with different subspecies such
as H.s. neanderthalensis or H. s. idaltu
•
Modern – 50,000 years BP to present
 Fully modern behavior& anatomy
becomes prominent.
 Ritual burying; reproduced tools of bone
& antlers; fishing (costal sites show
evidence of fishing after 50k ya).
 First hominids to reach Australia
(language?).
 Cultural universals emerge: art, music,
religion.
 Sometimes called Homo sapiens
sapiens
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.
http://www.youtube.com/watch?v=doF4sNrQtmg&feature=related
http://www.youtube.com/watch?v=MIQNzbd4-RY
Upper Palaeolithic – Hotbed of Culture
• 40 – 10k yBP
• Shelters
 15,000 yBP Ukraine
 Some made with mammoth
bones
 Wood, leather working;
carpentry
• Tools
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
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
Early 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. (Western
Europe to Siberia)
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 or abundance.
Venus of Willendorf.
Discovered in 1908 in Austria
and dated to approximately
23,000 years ago.
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
http://www.youtube.com/watch?v=oSHKqX8_pqU&feature=related
The Hominid Family Tree
• In 1995, hominid fossils dating 4.2 million
years old were found in the Rift Valley of
Kenya
 they were assigned to the species
Australopithecus anamensis
 they represent an intermediate form between
apes and A. afarensis
 this species represents a base of the family
tree for human evolution
The Hominid Family Tree
• Scientists have taken two different
approaches in classifying the species of
Homo
 “Lumpers” recognize three species of Homo,
focusing on common elements among fossils
and attributing the differences to diversity
within the group
 “Splitters” recognize at least seven species of
Homo
Figure 27.5 A hominid evolutionary tree
African Origin: Early Homo
• Homo rudolfensis
 described from a specimen discovered in 1972 with a
larger brain capacity than H. habilis
• Homo ergaster
 a species used to describe specimens that have a
larger brain capacity than H. rudolfensis and a
skeleton more like modern humans and less like
australopithecines
Brain size increased as Homo
evolved
Out of Africa: Homo erectus
• The oldest specimen of H. erectus is from
Africa, indicating that H. erectus arose in
Africa
• Homo erectus survived for over a million
years, longer than any other species of
human
• Homo erectus disappeared about 500,000
years ago in Africa, but the species
survived even longer in Asia
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
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
Our Own Species also Evolved in
Africa
• Modern humans first appeared in Africa
about 600,000 years ago
• According to some scientists, there have
been three species of modern humans
 Homo heidelbergensis
 Homo neanderthalensis
 Homo sapiens
Our Own Species also Evolved in
Africa
• Homo heidelbergensis is the oldest known
modern human
 an Ethiopian fossil dates back to 600,000 years ago
 it co-existed with H. erectus in Africa but had more
advanced features
 it had a bony keel running along the midline of the
skull, a thick ridge over the eye sockets, and a large
brain
 its range included parts of Africa, Europe, and
western Asia
Our Own Species also Evolved in
Africa
• About 130,000 years ago, Homo
neanderthalensis appeared in Europe
 compared to modern humans, Neanderthals
were short, stocky, and powerfully built
 their skulls were massive
Our Own Species also Evolved in
Africa
• The oldest known fossil of Homo sapiens is
130,000 years old and occurred in Africa
• Outside of Africa and the Middle East, the
earliest known fossils of H. sapiens are no older
than 40,000 years old
• This implies that Homo sapiens first evolved in
Africa and then migrated to the rest of the world
Our Own Species also Evolved in
Africa
• Recently-Out-of-Africa model
 this view of Homo evolution states that Homo
sapiens evolved in Africa and then migrated
to Europe and Asia
• Multiregional hypothesis
 this view of Homo evolution states that the
human races evolved independently from
Homo erectus in different parts of the world
Our Own Species also Evolved in
Africa
• Studies of human mitochondrial DNA (mtDNA) and
chromosomal nuclear DNA have helped to clarify the
controversy over the origin of Homo sapiens
 because DNA accumulates mutations over time, the oldest
populations should show the greatest genetic diversity
 all modern humans of different ethnic backgrounds share
common ancestor dating back 170,000 years ago
 only 52,000 years ago do Africans separate from non-Africans
 essentially the migration of Homo sapiens out of Africa followed
the same paths taken by Homo erectus half a million years
before
Out of Africa---many times
The Only Surviving Hominid
• Neanderthals
 this species of modern human were common in Europe in Asia
around 70,000 years ago
 they made diverse tools and lived in huts or caves
 they did not interbreed with members of Homo sapiens
• Cro-Magnons
 fossils of these early members of Homo sapiens date back as
late as 100,000 years ago in Europe
 they appear to have completely replaced the Neanderthals
around 34,000 years ago
 they used sophisticated tools and likely had full language
capabilities
Homo sapiens
• Archaic – 100,000 to
35,000 years BP
(before present)
 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
The Only Surviving Hominid
• Modern Homo sapiens
 humans eventually spread across Siberia to
North America about 13,000 years ago
• a recent genomic survey provides clear evidence
 human evolution has been characterized by
an increase in brain size and the ability for
conceptual thought
Figure 27.10 Homo sapiens is
still evolving