1. Human Evolution

2. 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

3. 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

4. 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.

5. 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

6. 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

7. Figure 27.1 A primate evolutionary tree

8. Hominin Diversity: Fossil Sites in the Old World

9. 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

10. How the Apes Evolved Hominoids evolved from anthropoid ancestors
hominoids are comprised of the apes and the hominids (humans and their direct ancestors)

11. 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

12. 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.

13. 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

14. 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)

15. Figure 27.3 Walking upright has evolved many times among vertebrates

16. A comparison of ape and hominid skeletons

17. The first of our genus: Early Homo

18. 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?)

19. 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.

20. Figure Homo habilis

21. 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
Artist rendition of H. habilis.
ER-1813 – Homo habilis

22. 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.

23. 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.

24. Figure Homo ergaster

25. 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

26. 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

27. Homo (ergaster) erectus
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.

28. 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.

29. 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

30. 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.

31. 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
Range of Homo neanderthalensis
The skull of the classic Neandertal found in 1908 at La Chapelle-aux-Saints.
First reconstruction of Neanderthal man.

32. 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

33. 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

34. 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

35. 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.

36. 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

37. 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.

38. Archaic H. sapiens Culture
Cave paintings from 20,000 years ago at Vallon-Pont-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

39. 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

40. 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

41. Figure 27.5 A hominid evolutionary tree

42. 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

43. Brain size increased as Homo evolved

44. 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

45. 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.

46. 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

47. 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

48. 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

49. 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

50. 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

51. 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

52. 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

53. 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

54. 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

55. Out of Africa---many times

56. 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

57. 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

58. 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

59. 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

60. Figure 27.10 Homo sapiens is still evolving