Human Evolution. The Evolutionary Path to Humans Begins with Early Primates The story of human...
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Transcript of Human Evolution. The Evolutionary Path to Humans Begins with Early Primates The story of human...
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:
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
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)
Hominin 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?)
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.
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 LeakeysER-1813 – Homo habilis
Artist rendition of H. habilis.
Oldowan Tool Industry• Chopper with simple edge
• Chopping tool
• Unretouched biface
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.
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.
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) erectus1891 - Eugene Dubois discovers H. erectus in JavaDubois 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 industryAll 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
• 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.
Range of Homo neanderthalensis
First reconstruction of Neanderthal man.
http://www.youtube.com/watch?v=CgEFoY-hoT4&feature=SeriesPlayList&p=39B8670A9074CF60&index=2
http://www.youtube.com/watch?v=5OJcS3y3mlI&feature=SeriesPlayList&p=39B8670A9074CF60&index=0
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 caveBottom: 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 competitionhttp://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 SapiensRegional-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 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 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
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
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
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 JavaDubois calls it Pithecanthropus erectus initially, also dubbed “Java Man”finds in China called Sinanthropusdates 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 caveBottom: 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
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