Primate Evolution(65 - 5 mya)

Emergence of PrimatesFirst primates

Plesiadapiforms or adapids and omomyids?Environment - Cretaceous to Palaeocene

Continental drift (Pangea = Laurasia & Gondwanaland)Success of primates

Arboreal theory Visual predation hypothesis (Cartmill 1972, 1992)

Early Primates

Prosimians (65mya)Monkeys (35mya)Apes (23mya)Hominids (5mya)

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

Continents at the end of the Meszoic

Here are the placement of the continents at the end of the Cenozoic and beginning of the Mesozoic, about 65 m.y.a.

The primate order is divided into two subordersThe prosimians, or lower primates

include the lemurs, lorises, tarsiers, and tree shrews, while the anthropoids, or higher primates

include monkeys, apes, and humans

Classification of Primates

Prosimians are generally small ranging from species the size of a mouse up to those as large as a house cat

They are arboreal, have five digits on each hand and foot with either claws or nails, and are typically omnivorous

They have large, forwardly directed eyes specialized for night vision, hence most are nocturnal

Prosimians

Tarsiers are prosimian primates

• Ring-Tailed Lemurs are also prosimians

As their name implies pro means "before," and simian means "ape”. prosimians are the oldest primate

lineage, and their fossil record extends back to the Paleocene.

During the Eocene prosimians were abundant, diversified, and widespread in North America, Europe, and Asia.

Prosimians

Early Cenozoic PrimatesThe earliest primates date to the first part of the Cenozoic

(65-54 m.y.a.).The Eocene (54-38 m.y.a.) was the epoch of prosimians

with at least 60 different genera in two families. The omomyid family lived in North America, Europe, and

Asia and may be ancestral to all anthropoids. The adapid family was ancestral to the lemur-loris line.

Notharctus, a primitive Eocene prosimian; found in North America.

Eocene Prosimian

Omomyid

An artist’s reconstruction of Shoshonius, a member of the Eocene omomyid family.

AnthropoidsAnthropoids branched off from the prosimians during the

Eocene. Anthropoid eyes are rotated more forward compared to

prosimians. Anthropoids have a fully enclosed bony eye socket. Anthropoids have a dry nose separate from the upper lip. Anthropoids have molar cusps.

New World Monkey

New World Monkeys constitute a superfamily belonging to the suborder Anthropoidea (anthropoids)

Another superfamily of the anthropoids: the Old World Monkeys

Old World Monkey

The third superfamily is the great apes, which include gorillas and chimpanzees.

Great Apes

Undisputed remains of early anthropoids date from 34 million years ago; Fayum area southwest of Cairo, Egypt Found remains from different types of anthropoids,

including: Parapithecids (monkey-like) Propliopithecids (ape-like) - some believe that the

common ancestor for both Old and New World monkeys belonged to this group Best known of group - Aegyptopithecus which is believed to

be after the fashion of the howler monkey

Early Anthropoids

Skull of Aegyptopithecus zeuxis

One of the Earliest Anthropoids

Miocene Period: 24 to 5.2 million years ago First hominid appeared in Africa where remains have been found dating

5 million years old Early Miocene Period

Proconsul found in sites in East Africa Middle Miocene

Kenyapithecus 16 to 10 million years ago with molars resembling modern hominoids

Late Miocene Apes Movement to Europe and Asia due to warmer weather conditions;

migration from Africa Two main groups:

Sivapithecus - link to orangutans Dryopithecus

Miocene Anthropoids

Proconsul

A skull of Proconsul africanus from the Kenya National Museum.

Proposed appearance of Proconsul africanus.

Kenyapithecus

Fossil jaw bones fromEquatorius, probably ancestral to Kenyapithecusafricanus and K. wickeri.

SivapithecusSivapithecus belongs to

the ramapithecid genera along with Gigantopithecus.

Sivapithecus is now believed to be ancestral to the modern orangutan.

A Sivapithecus skull.

GigantopithecusGigantopithecus is the largest

primate that ever lived, some standing over 10 feet tall and weighing 600 pounds.

Since it died out around 250,000 years ago, it coexisted with Homo erectus.

Some people believe it is still alive today as the yeti and bigfoot.

A reconstruction of Gigantopithecus by Russel Ciochon and Bill Muns.

Dryopithecus Dryopithecus lived in Europe

during the middle and late Miocene.

This group probably includes the common ancestor of the lesser apes (gibbons and siamangs) and the great apes.

Dryopithecus has the Y-5 arrangement of molar cusps typical of Dryopithecus and of hominoids.

OreopithecusOreopithecus bambolii lived between 9-7 m.y.a and spent

much of its time standing upright and shuffling short distances.

Its big toe splayed out 90 degrees from the other toes.Oreo is Greek for “mountain”

Early Hominids

Chronology of Hominid EvolutionThe Pleistocene (2 m.y.a. to 10,000 B.P.) is the epoch of

human life. Lower Pleistocene (2 to 1 m.y.a.): Australopithecus and early

Homo Middle Pleistocene (1 m.y.a. to 130,000 B.P.): Homo erectus

and archaic Homo sapiens Upper Pleistocene (130,000 to 10,000 B.P.): modern Homo

sapiens

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)Sc

ale:

Mill

ions

of Y

ears

BP

The Varied AustralopithecinesThere are two major hominid genera: Australopithecus and

Homo.However, in 1992 Berhane Asfaw and Tim D. White

discovered substantial remains considered to be from hominids ancestral to the australopithecines; these remains have been called Ardipithecus ramidus (thus establishing a third hominid genus) and dated a 4.4 m.y.a.

A more recent (1995, by Maeve Leakey and Alan Walker) discovery has been named Australopithecus anamensis and been dated at 4.2 m.y.a.

Evolution of BipedalismTool 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)

Skeletons

Comparison of human and chimpanzee skeletons.

Pelves

A comparison of human and chimpanzee pelves.

Dentition

Comparison of dentition in ape, human, and A. afarensis palates.

Crania Comparison

New World MonkeyGreat Ape

Human

Hominids show a trend toward a large and internally reorganized brain.An increase in brain size and organization is apparent when comparing the brains of the new world monkey, the great ape, and the human.

Discovered in Chad in 2002 and dated at nearly 7 million years, this skull is presently the oldest known hominid

Sahelanthropus tchadensis

The Species of Australopithecus Ardipithecus ramidus 4.4 - ? million years agoA. anamensis 4.2 - 3.9A. afarensis 4.2 - 2.5A. bahrelghazali 3.5 - 3.0A. africanus 3.5 - 2.5P. aethiopicus 2.7 - 2.3A. garhi 2.5 - ?P. boisei 2.3 - 1.3P. robustus 2.0 - 1.0

Phylogenetic Tree

Phylogenetic tree for African apes and hominids.

Ardipithecus ramidusHominid who walked bipedally 4.4 myaDiscovered in 1992 by Tim White in Aramis, Ethiopia (as

yet largely unpublished)Distinct enough to be a new species?

ape-like dentition bipedal locomotion overall hominid-like skeleton small cheek teeth with thin enamel and large canines arm bones are hominid-like foramen magnum indicates bipedalism

Australopithecines: Robust or Gracile?Two species of australopithecines: robust and gracileMost palaeoanthropologists classify robust species as

Paranthropus and gracile species as Australopithecus, although both species are australopithecines.

Gracile A. anamensis, A. afarensis, A. bahrelghazali, A. africanus, A.

garhi smaller dentition, lighter musculature

Robust P. aethiopicus, P. boisei, P. robustus larger teeth, massive jaws, sagittal crest

Australopithecines

Skulls of Robust (left) and Gracile (right) Australopithecines.

Australopithecus anamensis

4.2 - 3.9 myaaverage weight - 110 poundsprimitive bipedalism, possibly

climbingfound primarily in Kenyadiscovered in 1995

Australopithecus afarensis4.2 mya, with oldest definite specimen placed at 3.8 myaapelike features (long arms, prognathic face, toothrow, brain

capacity)pelvis, leg, feet, and foramen magnum all indicate bipedalism

first discovered by Don Johanson in 1974 and called “Lucy”

thought to be the “missing link” until A. anamensis was discovered 20 years later

Australopithecus afarensisLeft: Trail of footprints of A. afarensis made in volcanic ash, discovered by Mary Leakey at Laetoli.

Right: Close-up of footprint at Laetoli

Re-creation of a Pliocene landscape showing members of Australopithecus afarensis gathering and eating various fruits and seeds.

Landscape with A. afarensis

Australopithecus bahrelghazali3.5 - 3.0 myadiscovered by Michel Brunet in Bahr el Ghazal, Chad in

1995assumed bipedalism (few post-cranial remains)

A. africanus

3.5 - 2.5 mya 3.8 - 4.5 feet tall, 55-

130 lbs ape-like tibia, grasping

big toes wide pelvis, parabolic

tooth row primitive bipedalism first found by Raymond

Dart in Taung, South Africa in 1925

Australopithecus garhipossibly the direct ancestor of early Homo larger molars than afarensis, but not as large as

Paranthropus lacks enlarged brain of early Homo toolmaker and butcher2.5 mya

Paranthropus aethiopicus2.7 to 2.3 myaearliest robust australopithecine, but least well known larger dentition, cheek bones, dish-shaped faces, sagittal

crestsresembles afarensis but with increases in dental apparatus

sizeassumed bipedalismfirst discovered in Omo, Ethiopia, 1967-1974

The Black Skull - P. aethiopicus

The “black skull”, dated to 2.5 m.y.a., was discovered by Alan Walker in 1985 near Lake Turkana.

Paranthropus boisei2.3 - 1.3 mya; 4.1 - 4.5 feet tall, 75-175 lbsdiscovered by Louis Leakey at Olduvai Gorge in Tanzania

in 1959originally named Zinjanthropusdished face, sagittal crestparabolic toothrow, wide pelvisprimitive bipedalism

Paranthropus robustus2.0 - 1.0 mya; 3.6 - 4.3 feet tall; 70-175 lbsdiscovered by Robert Broom in 1938 at Kromdraai, South

Africa, who created the name Paranthropusdished face, sagittal crestparabolic toothrow, human-like big toes, wide pelvis, no diastema for caninesbipedalism (more primitive than modern human walking)

Map of Australopithecine Finds

Map of Australopithecus sites in Africa, with a focus on the East African rift valley and limestone caves of South Africa.

Facts about AustralopithecinesSpecies Dates

(m.y.a.)Known

Dist.Important

SitesBody

Weight(Mid-sex)

Brain Size(Mid-sex)

(cm3)Homo sapiens sapiens

modern world-wide Beijing, New York, London, Nairobi

60kg/132lbs 1,350

Pan troglodytes modern central Africa

Gombe, Mahale

42kg/93 lbs 390

Australopithecus boisei

2.6? to 1.2 E. Africa Olduvai, East

Turkana

39 kg/86 lbs 490

Australopithecus robustus

2.6? to 2.0? S. Africa Kromdraai Swartkrans

37 kg/81 lbs 540

Facts about AustralopithecinesSpecies Dates

(m.y.a.)Known

Dist.Important

SitesBody

Weight(Mid-sex)

Brain Size(Mid-sex)

(cm3)

Australopithecus africanus

3.0 to 2.5? S. Africa Taung, Sterkfontein

36 kg/79 lbs 490

Australopithecus afarensis

3.8 to 3.0 E. Africa Laetoli, Hadar

35 kg/77 lbs 430

Australopithecus anamensis

4.2 E. Africa Kanapoi Insufficient data

no published

skulls

Ardipithecus ramidus

4.4 E. Africa Aramis Insufficient data

no published

skulls

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

A reconstruction of the skull of Homo erectus, a widely distributed species whose remains have been found in Africa, Europe, India, China, and Indonesia.

Skull of Homo erectus

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.

Neanderthal Skull

Reconstructed Neanderthal skull

The Neanderthals were characterized by prominent heavy

brow ridges and weak chin

Homo neanderthalensisdiscovered in the Neander Valley

(Tal) near Dusseldorf, 1856massive 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.

Homo sapiensArchaic – 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 humans35,000 years B.P. in western Europe to 17,000 years B.P.1,600 cc cranial capacityName comes from a hotel in FranceNot a different species, just old Homo sapiens from Europe

Artist’s reconstruction of a Cro-Magnon man

Archaic H. sapiens Culture

ArtTraces of art found in beads, carvings, and paintingsCave paintings in Spain and southern France showed a marked degree of skill

Female figurines27,000 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

Cave paintings from 20,000 years ago at Vallon-Pont-d’Arc in southern France (left) and from Lascaux, in southwest France

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 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.

Social Organization

Hunter-gatherer analogy Small group, low population density, nomadism, kinship

groupsMigration

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