anthro final

(11.3-11.5 Lectures)

Paranthropus robustus

Date: 1 to 2.0 MYBP

Sites: Swartkrans, Dreimulen, Kromdraai (South Africa)

Specimen: SK 48

Large zygomatic arch and sagittal crest

Paranthropus aethiopicus

Date: 2.5 MYBP

Site: Lake Turkana

Small brain

Posterior foramen magnum

Massive sagittal keel

Very wide zygomatic arch

Specimen: KNM-WT 17000

Paranthropus boisei

Originally called “Zinjanthropus”

Date: 1.2 to 2.3 MYBP

Site: Olduvai Gorge

Massive molars with extensive wear

Reduced canines and incisors

Sagittal crest

Broad zygomatic arch

Gorilla-size brain

Wide distribution into Ethiopia

500–550 cc brain

Wide, massive zygomatic arch

Persists in East Africa to nearly 1.2 MYBP alongside Homo species

From Australopithecus to Homo

Australopithecines

Transitional forms

Early Homo

Late Homo

Transitional forms

Premeditation and Planning in Primates

Social learning is one thing, but what about planning and forethought?

Recent news describes “premeditation” by a chimpanzee who collects and stockpiles stones to throw at zoo visitors.

(12.1-12.3 Lectures)

Notable transitional species include:

Homo habilis (1.8 million years ago):

Transitional features between Australopithecus and Homo.

Smaller molars and larger incisors compared to Paranthropus.

Rounded cranium and reduced facial features, particularly orbital torus size.

Brain size: Smaller than Homo rudolfensis, but larger than modern great apes.

Homo rudolfensis (1.8 million years ago):

Larger brain (~775 cc) compared to Homo habilis.

Vaulted cranium, thicker bones, larger incisors and canines, but smaller molars.

Considered separate from Homo habilis due to differences in brain size, gracile features, and evidence against sexual dimorphism.

Australopithecines

Key Adaptations:

Bipedalism

Some adaptations for suspensory locomotion

Body Proportions:

Slightly longer arms compared to legs, though less pronounced than in apes

Feet:

Slightly divergent big toes, indicating early bipedal adaptation

Habitat:

Lived in a mosaic of grassland and forest environments

Dentition:

Larger molars and reduced canines compared to Homo species

Brain sizes similar to modern apes

Sexual Dimorphism:

Moderate to high in Paranthropus

Moderate in Australopithecus

Low in Homo species

Transition to Homo Species

Smaller teeth and jaws

Larger brain sizes

Less robust facial features

Greater reliance on tools and social learning

Evolutionary Trends

As human ancestors evolved into Homo erectus and later species, several trends became evident:

Increasing brain size (up to 850 cc and more)

Complete bipedalism with human-like limb proportions

Reduced facial robustness

Bowl-shaped pelvis suited for long-distance walking

Gradual expansion beyond Africa into Europe and Asia

Homo erectus

Time Period: Appeared around 1.75 million years ago

Tool Use:

Used Oldowan tools

Developed Acheulean tools (teardrop-shaped, bifacial)

Control of Fire:

Evidence from archaeological sites indicates fire use and cooking

Geographic Spread:

Fossils found across Africa, Europe, and Asia

Occupied a wide range of habitats

Lifestyle:

Likely nomadic and foraging-based