Exam 3 - Biological Anthropology

What does hominid refer to?

All great apes and humans

What does hominin refer to?

Humans and their ancestors after splitting from chimpanzees

How old is the hominin lineage?

Around 6-7 million years old

What is habitual bipedalism?

Walking upright on two legs as the normal form of locomotion

What are some unique traits of human dentition?

Smaller canines, parabolic arcade, Y-5 molar pattern

What is the material culture in human evolution?

The use and creation of tools and other physical objects

How has brain size changed in human evolution?

Significant increase compared to other primates.

What does “long developmental period“ mean in humans?

Humans grow and mature slowly, with longer childhoods

What is mosaic evolution?

Different traits evolving at different times

What is the human dental formula?

2.1.2.3

Human dental formulas are the same as what?

All Catarrhines

What is the Y-5 molar pattern?

A molar with 5 cusps forming a Y-shape, found in apes and humans

What is the CP3 honing complex in apes?

A system where the upper canine sharpens against the lower third premolar

What happens to the CP3 complex in humans?

It is lost due to canine reduction

How does sexual dimorphism differ in humans?

It is reduced compared to other apes

What does reduced sexual dimorphism suggest?

Less male-male competition and different social behavior

What is a humans dental arcade?

Parabolic

What is a chimps dental arcade?

U-shaped

What anatomical change supports bipedal balance?

Center of gravity aligned over the midline

What is the foramen magnum?

It’s the hole in the skill where the spine connects

How does the foramen magnum differ in humans?

It is underneath the skull

What spinal curvatures help with bipedalism?

Cervical and lumbar curvatures

Why are human lumbar vertebrae larger?

To support more body weight

What is the intermembral index?

Ratio of arm to leg length

What is the intermembral index for chimps?

110%

What is the intermembral index for humans?

70%

How is the human pelvis different?

It is short and broad with rotated ilia for upright walking

What is the valgus angle of the knee?

The inward angle of the femur that keeps feet under the center of gravity

How is the human foot adapted for walking?

Non-opposable big toe, large heel, and foot arches

What muscles are used for chewing?

Temporalis and masseter

What facial bone features are related to chewing in apes?

Sagittal crest and robust zygomatic arches

How does facial prognathism differ in humans?

Humans have less facial projection than apes

What are the social explanations for bipedalism?

Carrying food and provisioning in monogamous relationships

What are the ecological explanations for bipedalism?

Moving efficiently across forests, finding food, spotting predators

What are the four genera of early hominins discussed in lecture?

Sahelanthropus, Orrorin, Ardipithecus kadabba, Ardipithecus ramidus

What is the major geographic regions where early hominins were found?

East African Rift Valley

What are key evolutionary novelties of humans?

Bipedalism, changes in dentition, material culture, increased brain size, long development and lifespan

What is the significance of the foramen magnum position in hominins?

A forward position indicates bipedal locomotion

Where was Sahelanthropus techadensis discovered?

Chad

How old is Sahelanthropus techadensis?

7-6 million years

What are key traits of Sahelanthropus techadensis?

Vertical face, small canines, no C-P3 honing complex, forward foramen magnum, small brain

Where was Orrorin tugenesis found?

Kenya

How old is Orrorin tugenesis?

6 million years

What does the femur of Orrorin suggest?

It indicates possible bipedalism

What are some primitive traits of Orrorin?

Ape-like large canines

What is the age for Ardipithecus kadabba?

5.8-5.2 million years

What is the age for Ardipithecus ramidus?

4.4 million years

What environmental context is Ar. ramidus reconstructed in?

More closed, wooded habitats

What are important physical traits of Ar. ramidus indicating bipedalism?

Forward foramen magnum, short broad ilium in pelvis

What primitive traits did Ar. ramidus retain?

Small brain, prognathism, divergent big toe

What is the significance of Ar. ramidus in hominin evolution?

It shows a mix of primitive and derived traits; may be an early hominin or a side branch

What is Lovejoy’s model about?

A model for the origins of bipedality based on Ar. ramidus

What are trends seen in Australopiths?

Reduced canines, large cheek teeth, adaptations for bipedalism, small brain, small body with sexual dimorphism

What is the difference between Australopithecus and Paranthropus?

gracile

What is the difference between Australopithecus and Paranthropus?

Robust with chewing adaptations and larger postcanine teeth

Two main types of australopiths

Australopithecus (gracile) and Paranthropus (robust)

What traits are common to all australopiths?

Bipedalism, small brain, reduced canines, large cheek teeth, thick enamel

Who discovered the first Australopithecus fossil?

Raymond Dart

What was the Piltdown Hoax?

A fake fossil that delayed acceptance of Australopithecus as a human ancestor

Where were Australopithecus fossils mostly found?

Eastern and southern Africa

How old is Australopithecus anamensis?

4.2-3.9 million years

Where was Australopithecus found?

Kenya and Ethiopia

What evidence of bipedalism exists for A. anamensis?

Tibia with enlarged top end

What species is “Lucy“?

Australopithecus afarensis (3.9-2.9 Ma)

Where was A. afarensis found?

East Africa: Kenya, Tanzania, Ethiopia

What is the age range of A. afarensis?

3.9-2.9 million years

What are some key traits of A. afarensis teeth?

Reduced canines, bicuspid premolars, thick enamel

What does thick enamel in A. afarensis suggest?

Diet included nuts, grains, or hard fruits

What are bipedal features in A. afarensis?

Pelvis, valgus knee, forward foramen magnum, arches, heel

What are the Laetoli footprints from?

Tanzania

What species made the Laetoli footprints?

A. afarensis

What are some arboreal traits of A. afarensis?

Mobile shoulder, long arms, curved hand bones

What kind of environments did A. afarensis live in?

From closed woodlands to dry grasslands

How does Australopithecus africanus compare to A. afarensis?

Less prognathism, rounder braincase, slightly bigger brain

Where was A. africanus found?

South Africa

How old is A. africanus?

3.5-2 million years

What is the Taung Child?

Famous juvenile A. africanus fossil with brain endocast

What is dating South African sites difficult?

No volcanic ash for radiometric dating

What cranial feature is more developed in A. africanus males?

Robust jaw, big cheek teeth, nasal pillars

What is Australopithecus garhi known for?

Possible tool use, 2.5 million years, East Africa

What species shows a mix of Australopith and Homo traits?

Australopithecus sediba

How old is Australopithecus sediba?

2 million years

Where was Australopithecus found?

South Africa

What environmental shift happened around 2.6 million years ago?

Cooling and spread of grasslands

What are the evolutionary trends seen after 2.5 million years ago?

Bigger brains, more tools, less prognathism, smaller teeth

What is Kenyanthropus platyops?

3.5 million years ago hominin with flat face and small molars

What is Kenyanthropus platyops thought to possibly be?

A. afarensis

What includes Australopiths?

Australopithecus and Paranthropus

What do Australopiths show?

Clear signs of bipedalism and small brain sizes

What dental features define australopiths?

Reduced canines, large cheek teeth, thicker enamel

What locomotor traits are seen in australopiths?

Definitive adaptations for bipedalism

What bipedalism traits are shown in australopiths>

Valgus knee and short broad pelvis

Average brain size of Australopithecus afarensis

435 cm³

Do australopithecus afarensis have a significantly larger brain size than apes?

No

Who discovered first Australopithecus fossil?

Raymond Dart (taung child, 1924)

What was the Piltdown Hoax?

A fraudulent fossil that delayed acceptance of African human origins by suggesting a large-brained early human in England

3 key bipedal traits in A. afarensis

forward foramen magnum, pelvis adapted for upright walking, valgus knee

A. afarensis

had adducted (non-grasping) big toe and human-like walking gait

What arboreal traits did A. afarensis retain?

long upper limbs, curved finger bones, mobile shoulder joints

What environments did A. afarensis live in?

Varied; woodlands to open grasslands in East africa