World Archaeology - Jan 12

Describe phylogeny

• All living humans are members of the species Homo sapiens

• Humans and our ancestors + the great and lesser apes are all members of superfamily Hominoidea

Describe genetic evidence

Describe fossil records

• Paleoanthropologists specialize in the study of the hominoid lineage

• Miocene explosion in the number of hominoid species

Date/Brain size/characteristic/found in: Australopithecus

1. 4.0-2.5 million years ago

2. 450-475 cc

3. Bipedal

4. East Africa, West Africa, and South Africa

Date/Brain size/characteristic/found in: Kenyanthropus

• 3.5 million years ago

• 450-475 cc

• Similar to Australopithecus

• East Africa

Date/Brain size/characteristic/found in: Paranthropus

• 2.5-1.4 million years ago

• 450-475 cc

• Massive molars and chewing muscles

• East Africa and South Africa

Date/Brain size/characteristic/found in: Homo habilis

• 2.5-1.6 million years ago

• 500-800 cc

• Increased brain size

• East Africa and South Africa

Date/Brain size/characteristic/found in: Homo erectus

• 1.9 million 45-000 years ago

• 750-1,250 cc

• Further increase in brains size, dispersal out of Africa

• Africa, Asia, and Europe

Describe the hominin fossil record: early hominin radiation

Describe the hominin fossil record: Australopithecines

Describe the Laetoli footprints

Describe the new Laetoli footprints

• Found in Tanzania in 2016

• Provide evidence for marked body size variation in early hominins

Describe Laeotoli: bipedalism

• Discovered by Mary Leakey, 1976

• Laetoli, located just 70km SE of Olduvai Gorge

• Millions of years ago an active volcano covered the area with a layer of ash, followed by a light rain shower

• Earliest evidence of bipedalism: the human method of locomotion, walking on two leg

Describe the dating of Laetoli and early humans

• Australopithecus afarensis

• Absolute dating techniques

  • Rely on properties of radioactive decay: isotopes

  • Potassium-argon (Radiopotassium dating or K-Ar dating): can date some of the earliest rock on the plant

    • K (potassium found in granites, clays, and basalts)

    • K occurs in several stable forms and one radioactive form: 40K

    • The half-life of 40K is 1.3 billion years —> not used for young deposits

    • Laetoli dates to 3.8-3.5 million years ago

Describe the discovery of Lucy

• 11 years old

• 2.9 million years old

• 4 feet tall

• Crocodile teeth marks on pelvis

• Found in Hadar

  • Also found 200 bones from other adults

  • The group probably all died together - wiped out by a flash flood

Describe sexual dimorphism

• Sexual dimorphism: size difference between the sexes

• Indicative of polygynous mating systems

• Dimorphism among Australopithecus = close to 30%

Describe hominin fossil record: Kenyanthropus

• Fossil date to 3.5 Ma

• Were first discovered in 2001 in Kenya

• Similar to australopithecines, but still poorly understood

Describe hominin fossil record: Paranthropus

• Also known as robust Australopithecus

• Fossils date to 2.5-1.4 Ma

• Characterized by:

  • Massive molars

  • Large chewing muscles

  • Subsisted on diet of seeds and fruits

Describe the genus Homo

• Emerges 2.5 mya (!!)

• Overlaps with Aust

Describe hominin fossil record: Homo Habilis

• Fossils in East Africa date to 2.5 -1.7 Ma

• Sites include:

  • Olduvai Gorge (Tanzania)

  • Koobi Fora (Kenya)

• First hominin placed within genus Homo

• Larger brain than contemporaries/pr