ANTH1L final- human evolution

Relative dating

• Comparison/in relation to one another, not exact date

• Principle of superposition:

  • Oldest on the bottom, newest on the top

• Fluorine dating:

  • Two fossils; the one with more fluorine is more likely older

Absolute dating (Chronometric)

• “Exact” age

• Radio-carbon dating: C¹⁴ → N¹⁴

  • 5,730 yrs for half the Carbon¹⁴ to turn into Nitrogen¹⁴

  • half-life: the amount of time it takes for the parent to turn into the daughter

• Radio-potassium dating: K → Ar

  • Volcanic material

  • 1.3 billion years = one half-life

What epoch are we currently living in?

Holocene (10k ya)

What epoch were the first primates thought to appear?

Paleocene, 60mya

Did dinosaurs coexist with any primates in the Mesozoic era?

No

The first hominids were found toward the end of the Miocene; when was that?

5.3 mya

What time span does the Cenozoic era include?

66mya — present

Characteristics of the genus Australopithecus

• Small brain

• Ape-like head

• Rather human-like body

• Small canines and larger premolars/molars (called megadontia)

  • 3 groups:

    • gracile— smaller, “lighter” than robust species

    • primitive (same as gracile)

    • robust— cresting, huge molars, large zygomatics, large mandibles with tall ramus

  • legs:

    • angled femoral neck

    • shorter than our legs

  • feet:

    • convergent big toe

    • double arches

  • pelvis:

    • small

    • somewhat rounded iliac blade shape

Sahelanthropus tchadensis (S. tchadensis)

• Chad, Africa

• 320cc brain size

• 6-7mya

• considered hominid because of anterior foramen magnum

Ardipithecus ramidus— “Ardi”

• Ethiopia

• 380cc brain size

• 4.4mya

  • skull:

    • no cresting

    • anterior foramen magnum

    • flaring zygomatics

  • lower body:

    • divergent big toe

    • curved phalanges

    • angled femur

    • short & wide iliac blade shape

Paranthropus aethiopicus

• Ethiopia, Kenya and Tanzania in east Africa

• 2.5 mya

• Brain size 410 cc

Au. afarensis— “Lucy”

• primitive (gracile) Australopithecus

• 2.9 - 3.9 mya

• Ethiopia, Kenya, Tanzania

• Brain size:

  • 433—550 cc

ROBUST Australopiths

• Cresting

• Large molars

• Large zygomatics

• Large mandibles with tall ramus

  • Paranthropus aethiopicus

  • P. boisei

  • P. robustus

Homo habilis/rudolfensis

• short legs, long arms

• finger bones suggest a precision grip

• H. habilis:

  • Found in Tanzania

  • Cranial capacity: 600-700 cc

  • Time existed: 2.4–1.4 mya

• H. rudolfensis:

  • Found in Kenya

  • Cranial capacity: up to 775 cc

  • Time existed: 1.9–1.8 mya

  • generally larger skull/teeth than habilis

• Oldowan Tools

Homo erectus

• Homo erectus (“Peking Man”)

  • 850–1150cc brain size

  • Found in Asia

  • 1.6 mya—40k ya

• Homo ergaster (“Turkana Boy”)

  • 850–1250 cc brain size

  • Found in Kenya

  • 1.9 mya — to maybe 400k ya

• Homo georgicus

  • 600 cc brain size

  • Found in Republic of Georgia (Dmanisi)

  • 1.7 mya

Homo heidelbergensis

• 800,000 - 200,000 ya

• Europe, Africa, possibly Asia

• Compared to H. erectus:

  • Skull is higher and more well-rounded

  • Brow ridges still large

  • Less prognathic lower face

• Cranial capacity: average of 1206 cc

• More diverse than H. erectus

  • Varied tools (Acheulian)

  • Primitive shelters

  • More efficient hunting techniques

Homo neanderthalensis

• Germany, might have extended into Central Asia and Siberia

• 400-28k ya

• More complex stone tools (Mousterian)

• 1520 cc cranial capacity

• Shorter and bulkier than modern humans, more adapted to cold climates:

  • shorter limbs, barrel-like large ribcages, large skulls & noses

• Some modern humans have Neanderthal DNA in their genome

  • This means that Neanderthals were not a different species than modern humans, interbreeding took place when modern humans left Africa

Homo florensiensis

• Found in 2003 on the island of Flores in Indonesia

• As many as 12 found

• 94–13kya

• ~3ft tall

What skull is this?

Sahelanthropus tchadensis (S. tchadensis)

What skull is this?

Ardipithecus ramidus (“Ardi”)

What skull is this?

Homo neanderthalensis (H. neanderthalensis, neanderthal)

What skull is this?

Homo erectus/ergaster (H. erectus/ergaster, “Turkana Boy”)

What skull is this?

Homo habilis (H. habilis)

What skull is this?

Paranthropus boisei (P. boisei)

What skull is this?

Australopithecus africanus (A. africanus)

What skull is this?

Australopithecus afarensis (A. afarensis, “Lucy”)

What skull is this?

Cro-Magnon man (anatomically modern human)

What skull is this?

Homo florensiensis (H. florensiensis)