Today’s Topics

•      Our Closest Relatives—The Primates

•      Early Human Evolution – The Australopithecines

 

Apes: Gibbon

•      Many Species: Genus Hylobates

•      Southeast Asia

•      Small Body Size

 

Apes: Orangutan

•      Only One Species

•      Indonesian Islands: Sumatra & Borneo

 

Apes: Gorilla

•      One Species (3 Subspecies):

–   Mountain Gorilla

–   Western Lowland Gorilla

–   Eastern Lowland Gorilla

•      Tropical Africa

•      Knuckle Walking

 

Apes: Chimpanzees

•      Two Species:

–   Common Chimpanzee

–   Pygmy Chimpanzee (Bonobo)

•      Tropical Africa

•      Knuckle-Walking

 

Primate Studies: Tool Use

•      Chimpanzees & Orangutans

 

Primate Studies:
Intelligence & Language

•      Intelligence Studies

–   Learning

–   Tool Making

•      Language

 

Primate Studies: Diet & Hunting

•      Active Hunting; Food-Sharing

–    Especially Chimps

 

Primate Studies: “Culture”

•      Learned Behaviors Transmitted

•      Traditions; Different in Different Places

•      Chimpanzees & Orangutans

 

Primate Studies: Complex Social Networks

•      Learning; Reciprocity

 

Early Human Evolution

 

Divergence Times

•      Gibbon 15-20 mya

•      Orangutan 10-16 mya

•      African apes 5-9 mya

–   Gorilla 7-9 mya

–   Chimpanzees/Hominids 5-7 mya

 

Environmental Context

-Long-Term Cooling Trend

-Breakup of Tropical Forests (esp. last 5 million years)

 

•      Why did hominids diverge from other apes?

•      What can we say about the lives of early hominids?

 

Last Common Ancestor

•      Terrestrial but with some arboreal behavior

•      Omnivorous with possibly some hunting

•      Social

–   Some communication system

–   Reliance on visual clues and individual recognition

•      Limited tool use

 

Africa & Early Hominid Fossils

 

Early Fossil Finds

-Raymond Dart and Taung (1924)

-The Leakeys and Zinj (1959)

 

Earliest hominids

-Orrorin tugenensis

-Sahelanthropous tchadensis (5-7 mya)

-Early Australopithecines

            -Australopithecus ramidus

            -Australopithecus anamensis

            -Kenyanthropus platyops

 

Hominid Phylogeny from Kottak

 

Australopithecus ramidus

•      TIME: 4-5-4.3 mya

•      SITES: Aramis, Ethiopia

•      Tim White, Berhane Asfaw

•      Sometimes given own genus “Ardipithecus”

•      Earliest known hominid

 

Australopithecus anamensis

TIME: 3.9-4.3 my
SITES: Kanapoi and Allia Bay in Kenya
Meave Leakey

•      bipedal

•      about 47-55 kg

 

Kenyanthropus platyops

•      3.5 million years

•      Human like face

 

Australopithecus afarensis

•      TIME: 3.8 - 3 mya

•      SITES: Ethiopia and Tanzania

•      Don Johanson, Tim White, Mary Leakey

•      “Lucy”

 

•      Bipedal traits – pelvis, knee, foot

•      Long arms relative to legs

•      Hand bones show arboreality

 

Evidence for Bipedalism

 

Chimp / Human

 

Slide showing the orientation of skulls of humans, gorillas, and australopithecines

 

Slide showing lower limbs of humans, chimps, and A. afarensis

 

•      Small brain (400-500 cm3)

•      Reduced canine

•      Large Molars

 

Laetoli, Tanzania

-Footprints; 70 m trail; ~3.6 mya

 

Gracile & Robust Australopithecines

•      The Gracile Forms

–  Australopithecus africanus

•      The Robust Forms

–  Australopithecus robustus

–  Australopithecus boisei

–  Australopithecus aethiopicus

 

Gracile Australopithecines

•      A. africanus

•      South Africa

•      2-3 mya

•      Small Brain (450-500cc)

•      Generally gracile skull

 

Robust Australopithecines

•      A. aethiopicus

•      A. robustus

•      A. boisei

•      1.0 – 2.5 mya

•      South & East Africa

•      Small Brain

•      Huge Face & Jaws