Lab Final Monday 6:30 PM

Optional Lecture Exam 4Monday 6:00 PM

scantron

• Today:• Human Evolution

Darwin’s Finches Survivor Game

• Fossil Lab and Review

Class of 2011

• CONGRATULATIONS GRADUATES!

Primate and Human Evolution

• What is the human genealogy?• Who is the closest genetic relative? • Why are we different? When did we diverge?• What makes us human?• Are we still evolving?

• But first, how was the stage set for humans?

Who are we?

• Maiasaura, a Late Cretaceous ornithopod, nested in colonies in northern Montana

Meteorite Impact Mass Extinction

Global temperature models60 ma to present

Pleistocene CO2 Levels and Glacial Periods

• Sahelan-thropus tchadensis, – the oldest

known hominid – nearly 7 million

years old, – discovered in

2002 in Chad– “Tormai” –

Hope of Life

Our family goes back farther than we thought

• human-chimpanzee stock separated – from ancestral gorillas about 8 million

years ago

Humans and Chimpanzees Diverged

• human-chimpanzee stock separated • from ancestral gorillas ~ 8 million years ago

Sahelanthropus tchadensis~7 my ago – at or near the time – when humans and– chimpanzees diverged

Humans and Chimpanzees Diverged

• humans separated from chimpanzees about 5 million years ago

Sahelanthropus tchadensis -- mosaic of primitive and advanced features

• The small brain case and most of the teeth are chimplike

• The nose, which is fairly flat, –and the prominent brow ridges –are features only seen, until now, –in the human genus Homo

Oldest Hominid

• As recently as 2000, – the earliest fossil evidence of hominids – was from 4.4-million-year-old rocks in eastern

Africa

• Since then, as just noted, discoveries have pushed that age back to almost 7 million years

Continuing Discoveries Change Our Ideas

paleoanthropologists now think

– that human evolution is not a straight line – The lines branched many times

• According to this “bushy” model key traits evolved more than once• upright walking, •manual dexterity • “large” brain

– This probably produced many evolutionary

dead-ends

“Bushy” Model of Human Evolution

• These include changes in the skeleton – and mode of locomotion, – an increase in brain size, – a shift toward smaller, fewer, – and less specialized teeth,

Trends in Primates

Trends in Primates

the evolution of stereoscopic vision and a grasping hand with opposable thumb

Not all these trends took place in every primate group,

nor did they evolve at the same rate in each group

• The prosimians, or lower primates,

• while the anthropoids, or higher primates, – include monkeys, apes, and humans

Classification of Primates

• LowerTarsiers are prosimian primates

Tarsier

• Anthropoids are divided into three superfamilies– Old World monkeys, – New World monkeys, – and hominoids

Anthropoid Superfamilies

Great Apes

• Chimpanzees

Chimpanzee

One of the Earliest Anthropoids• Skull of

Aegyptopithecus zeuxis,

– one of the earliest known anthropoids

• evolved in Africa,• The hominids (family Hominidae)– the primate family that includes present-

day humans –and their extinct ancestors –have a fossil record extending back – to almost 7 million years

•

Hominoids

• Hominids are bipedal; – that is, they have an upright posture, –which is indicated by several modifications

in their skeleton

• Comparison between quadrupedal and bipedal locomotion– in gorillas and

humans

Comparison of Locomotion

• In gorillas the ischium bone is long – and the entire pelvis is

tilted toward the horizontal

• In humans the ischium bone is much shorter

• and the pelvis is vertical

Comparison of Locomotion

• Comparison between quadrupedal and bipedal locomotion– in gorillas and humans

• hominids show a trend – toward a large and internally reorganized

brain

Larger Reorganized Brain

Larger Reorganized Brain

– a present-day human

• Other features that distinguish hominids– a reduced face – and reduced canine teeth, – omnivorous feeding, – increased manual dexterity, – and the use of sophisticated tools

Other Distinguishing Features

• Many anthropologists think – these hominid features evolved in response – to major climatic changes – during the Miocene into the Pliocene

• During this time, vast savannas – replaced the African tropical rain forests – where the lower primates – had been so abundant

Response to Climatic Changes?

• Australopithecine is a collective term – for all members of the genus

Australopithecus• Currently, five species are recognized: –A. anamensis, –A. afarensis, –A. africanus, –A. robustus, –and A. boisei

Australopithecines

• Australopithecus afarensis, – which lived 3.9–3.0 million years ago, – was fully bipedal – and exhibited great variability in size and weight

• Members of this species ranged – from just over 1 m to about 1.5 m tall – and weighed between 29 and 45 kg

Australopithecus afarensis

• A reconstruction of Lucy’s skeleton – by Owen Lovejoy• and his students at Kent

State University, Ohio

• Lucy is an ~ 3.5-million-year-old – Australopithecus afarensis

individual • whose fossil remains were

discovered by Donald Johanson

Lucy• This

recon-struction

• illustrates how adaptations in• Lucy’s hip, leg and foot • allowed a fully bipedal • means of locomotion

• Preserved in volcanic ash at Laetoli, Tanzania– Discovered in 1978 by

Mary Leakey, – these footprints proved

hominids – were bipedal walkers at

least 3.5 million years ago

– The footprints of two adults and possibly those of a child

– are clearly visible in this photograph

Hominid Footprints

Hominid Footprints

• Most scientists think the footprints – were made by

Australopithecus afarensis

– whose fossils are found at Laetoli

• A. afarensis had a brain size of 380–450 cubic centimeters (cc), – larger than the 300–400 cc – of a chimpanzee – but much smaller than that of present-day

humans (1350 cc average)

Brain Size of A. afarensis

Landscape with A. afarensis• Re-creation of a

Pliocene landscape – showing members

of – Australo-pithecus

afarensis – gathering and

eating – various fruits and

seeds

• A reconstruction of the skull – of Australopithecus

africanus• This skull, – known as that of the

Taung Child, • was discovered by

Raymond Dart in South Africa in 1924

– and marks the beginning of modern paleoanthropology

Skull of A. africanus

• The earliest member of our own genus Homo – is Homo habilis, –which lived 2.5-1.6 million years ago–and coexisted with A. africanus – for about 200,000 years

The Human Lineage

• H. habilis had a larger brain (700 cc average) – than its australopithecine ancestors, – but smaller teeth

• It was about 1.2-1.3 m tall – and only weighed 32-37 kg

Characteristics of Homo habilis

– Homo erectus was a widely distributed species, – having migrated from Africa during the

Pleistocene• Specimens have been found – not only in Africa – but also in Europe, India, China ("Peking Man"), – and Indonesia ("Java Man")– Its brain size of 800-1300 cc

Homo Erectus

Skull of Homo erectus

• The archaeological record indicates – that H. erectus was a tool maker

• Furthermore, some sites show evidence – that its members used fire and lived in caves, – an advantage for those living – in more northerly climates

H. erectus Was a Tool Maker

Homo erectus Using Tools• Re-creation of a Pleistocene setting in Europe – in which members of Homo erectus are

– using fire and stone tools

• Currently, a heated debate surrounds the transition– from H. erectus to our own species, Homo sapiens– Paleoanthropologists are split into two camps

• On the one side are those who support – the "out of Africa" view

• According to this camp, early modern humans – evolved from a single woman in Africa, – whose offspring then migrated from Africa, • perhaps as recently as 100,000 years ago

– and populated Europe and Asia, – driving the earlier hominid populations to

extinction

The "Out of Africa" View

• established separate populations throughout Eurasia

• Occasional contact and interbreeding – between these populations enabled our species

to maintain its overall cohesiveness, – while still preserving the regional differences – in people we see today

The "Multiregional" View

• Regardless of which theory turns out to be correct, – our species, H. sapiens – most certainly evolved from H. erectus

Homo sapiens Evolved From H. erectus

• Perhaps the most famous of all fossil humans are the Neanderthals, – who inhabited Europe and the Near East – from about 200,000 to 30,000 years ago

• Some paleoanthropologists regard the Neanderthals – as a variety or subspecies of our own species

(Homo sapiens neanderthalensis), – whereas others regard them as a separate species

(Homo neanderthalensis)

Neaderthals

Neanderthal Skull• Reconstructed

Neanderthal skull

• The Neanderthals

were characterized • by prominent heavy

brow ridges and week chin

Burial Ceremony in a Cave

• Archaeological evidence indicates – Neanderthals lived in caves – and participated in ritual burials– as depicted in this painting of a burial ceremony

– such as occurred approximately 60,000 years ago – at Shanidar Cave, Iraq

• About 30,000 years ago, – humans closely resembling modern Europeans – moved into the region inhabited – by the Neanderthals and completely replaced them

• Cro-Magnons, the name given to – the successors of the Neanderthals in France, – lived from about 35,000 to 10,000 years ago; – during this period the development of art and

technology – far exceeded anything the world had seen before

Cro-Magnons

• Cro-Magnons were very skilled cave painters

– Painting of a horse – from the cave of Niaux, France

Painting From a Cave in France

• Re-creation of a Cro-Magnon camp in Europe

Cro-Magnon Camp

What makes us Human?

• Ability to walk upright – But hominids did that• Diversity of hand grips

– Ability to think abstractly• Early toolmakers did that

• Plan?• Civiliziations?• Technologoy?

• List three distinctions thatYOU believe set humans apart and state whether this is clearly advantageous to our lineage.

Closet genetic relative?

• How have chimps evolved compared to humans?

• How does altruistic tendencies set humans apart?

• Buffon, 18th century said“Genius is only a great aptitude for patience”