Outline 22:Hominid Fossil Record

Human ancestors

A.=Australopithicus

Assumed direct lineage to modern humans

Babcock textbook

Lots of names but pattern is clear that Homoevolved from an australopithecine over 2 m.y. ago.

Collecting hominid fossils in East Africa

Using Stratigraphy and Radiometric Dating of volcanic ash beds to date hominid fossils

Hominid Jawbones from Ethiopia

Sahelanthropus tchadensis, 6.5 MY old

Sahelanthropus tchadensis,

6.5 MY old

Gorilla – female on left, male on right; note the sexual dimorphism

Orrorin tugenensis – the sum total of specimens

Ardipithecus ramidus, 2009

Australopithecus anamensis

The Australopithecines

• Ardipithecus: oldest definite bipedal ancestor, over 4 M.Y. old

• Australopithecus: the gracile australopithecines

• Paranthropus: the robust australopithecines

Fossil Species

• Ardipithecus ramidus: 4.4 MY, teeth, jaws and bone fragments suggest it is a hominid, not a pongid.

• Australopithecus afarensis: 3.8-3.0 MY based on good fossils. Clearly a bipedal animal based on bones and fossil footprints.

Bipedal Footprints of Australopithecus in Lithified Volcanic Ash 4 MY old from

Tanzania. Found by Mary Leakey.

Australopithecuscouple making footprints in volcanic ash

Jawbones of Australopithecus afarensis

Fossil remains of “Lucy”, the most

complete specimen of

Australopithecus afarensis.

An adult skull, A. afarensis. The spinal cord opening is underneath the skull.

Pelvis of Australopithecus afarensis

Reconstruction of Australopithecus afarensis

Face-to-face with

A. afarensis

A troop of A. afarensisfeeding on tubers in the forest.

A. afarensisfamily unit crossing the savannah.

Fossil Species

• Australopithecus africanus: 2.8-2.5 MY• Robust australopithecines:

Paranthropus aethiopicus: 2.6-2.2 MYP. robustus: 2.0-1.2 MYP. boisei: 2.6-1.0 MY

The Taung Child, A. africanus

Skull of Paranthropus boisei

Paranthropus aethiopicus

Paranthropus aethiopicus

Justus Erus found the fossil

Kenyanthropus platyops, 3.5 MY old

from Kenya

Kenyanthropus rudolfensis or Homo rudolfensis?

Or Darth Vader?

Fossil Species

• Homo habilis: 2.5-1.6 MY• H. erectus: 1.8 MY- 25,000 yrs?

Java manPeking man

• H. sapiens: archaic vs. modern

Skull of Homo habilis

H. rudolfensis, H. habilis, and P.

boisei.Hominids in East Africa around 2

MY ago.

Phylogeny 2000.

One of many

hypotheses.

Homo erectus from Indonesia, Java Man

Skull of Homo erectus from China

Peking Man

Skeleton of Homo erectus, Turkana Boy from Kenya

H. erectus skull of Turkana Boy

The face of Homo erectus

Homo erectus using fire to sharpen spears

Homo sapiens?

• Archaic H. sapiens or unique species?H. antecessor: 800,000 years oldH. heidelbergensis: 500,000 years oldH. neandertalensis: 200,000-32,000

years old• Currently all thought to be unique

species.

Homo antecessor from Spain, 800,000 years old

Homo heidelbergensis, 500,000 years BP

Neanderthal skull, Spain

Fleshing out a Neanderthal skull

Neanderthal skeleton, Germany

Shanidar Cave, Iraq: Neanderthal burial, 50,000 yrs. BP

Shanidar Cave, Iraq: Neanderthal burial, 50,000 yrs. BP

Did Neanderthals have naked skin like we do? What would the Theory of

Neoteny say?

Reconstruction of Neanderthal child from Gibraltar, Spain, 30,000 years B.P.

http://www.bbc.co.uk/news/science-environment-19960748

How scientists recreated Neanderthal man

http://news.bbc.co.uk/2/hi/science/nature/8660940.stm

1%-4% DNA

500 ky

30 ky

2010: Genetic studies of Neanderthal bones indicates that between 1-4% of modern human DNA is from Neandertals. Suggests interbreeding around 60,000 years ago.

Fig. 1 Samples and sites from which DNA was retrieved.

R E Green et al. Science 2010;328:710-722

2010: Genetic studies of Neanderthal bones indicates that between 1-4% of modern human DNA is from Neandertals. Suggests interbreeding around 60,000 years ago.

Did light colored skin and hair come from Neanderthal genes?

http://www.cbsnews.com/news/modern-humans-more-neanderthal-than-once-thought-studies-suggest/

Homo sapiens

• modern H. sapiens: first appearancesEast Africa: 195,000 years agoMiddle East: 90,000 years agoAustralia: 50,000 years agoEurope: 32,000 years agoAmericas: 20,000 years ago

Homo sapiens,Israel, 90,000

yrs BPFYI: Abraham lived only 4,000 yrs BP

Cro-Magnon man from France, Homo sapiens, 28,000 years old

Homo floresiensis, a hobbit-size human from Flores Island, Indonesia, 18,000 BP

Modern human

Homo sapiens(Cro-Magnon people) drew the cave art in France and Spain about 17,000 years ago.

Lascaux, France, cave art

Other rock paintings

Life in the late Stone Age, which ended at different times on different continents.

The invention of farming, plus domestication of animals, started civilization.

Evolution of Modern HumansTwo Theories:

• Out of Africa: all modern humans descended from a single population. Racial differences have very recent origins.

• Multiregional Theory: modern humans evolved from local populations of H. erectus at several places in the Old World. Accounts for the racial differences in modern humans.

How far back in time did the modern races diverge from a common ancestor?

DNA studies show the common

ancestor of all humans lived in

Africa about 170,000 years

ago

Tree Diagram

of Genetic Similarity