Human Evolution: Key Fossils, Species, and Dating Methods

Piltdown

A fake early-human skull planted in England that tricked scientists for decades.

Taung

Site in South Africa where the Taung Child fossil was found.

Australopithecus africanus

Early human relative that walked upright and still climbed trees.

Ardipithecus ramidus

Very early human ancestor ("Ardi") that walked upright but also lived in trees.

Paranthropus boisei

Robust early hominin with huge jaws and teeth for chewing tough plants.

Features that were believed to link the Taung Child with modern humans

Small canines, upright posture, and a human-like brain shape.

Evidence for bipedalism in South African australopiths

Bowl-shaped pelvis, angled femur, arched feet, and the foramen magnum (skull base hole) underneath.

Features that might indicate that australopiths spent a good deal of time in trees

Curved fingers, long arms, flexible shoulders, and some grasping toe ability.

lesser gluteals

Hip muscles that keep the body balanced during upright walking.

Australopithecus afarensis

Species of "Lucy"; walked upright but still climbed well.

Laetoli

Site in Tanzania with 3.6-million-year-old footprints showing upright walking.

Paranthropus robustus

South African robust species with strong jaws and large teeth.

Australopithecus anamensis

Early bipedal species older than A. afarensis.

Orrorin tugenensis

Very early possible human ancestor with leg bones suggesting upright walking.

Sahelanthropus

One of the oldest possible human ancestors; skull suggests upright posture.

size dimorphism in australopiths

Males were much larger than females, showing strong male competition.

Homoplasy

Similar traits that evolve separately, not from a common ancestor.

Homology

Traits shared because they came from a common ancestor.

Cladistics

Method for grouping species based on shared ancestry.

Monophyly

A group including one ancestor and all of its descendants.

Paraphyly

A group including an ancestor but leaving out some descendants.

Polyphyly

A group that does not share a recent common ancestor.

Radiocarbon dating

Dates once-living things up to ~50,000 years old using carbon-14.

K/Ar dating

Dates volcanic rock using potassium and argon; good for millions of years old.

Palomagnetism (Paleomagnetism)

Dating rocks by how they record Earth's ancient magnetic field flips.

Ur/Pb dating (U/Pb)

Very precise dating using uranium turning into lead in rocks.

Intraspecific and interspecific variation

Intraspecific = differences within one species; interspecific = differences between species.

Carbon isotopes of chimp and hominins

Chimps eat C3 forest foods; hominins ate more C4 open-grass foods and meat.

Olduvai Gorge

Important site with early Homo fossils, tools, and animal bones.

Lomekwi

Site with the oldest known stone tools (~3.3 million years old).

Ledi-Geraru

Site with the earliest known Homo jaw (2.8 million years old).

Occlusal relief and diet

High tooth relief = cutting tough foods; low relief = grinding softer foods.

Incisor size and diet

Big incisors = fruit eating; small incisors = less fruit.

Dental microwear

Tiny scratches/pits on teeth showing what foods were eaten right before death.

Early Homo's differences from Australopithecus

Bigger brains, smaller teeth, flatter faces, more tools, more meat.

The Expensive Tissue Hypothesis

Humans got bigger brains by shrinking their guts and improving diet quality.

KNM ER 1470

Large-brained early Homo skull, often linked to Homo rudolfensis.

Hadar Homo

Early Homo fossils from Hadar showing a mix of primitive and advanced features.

Possible evidence for persistence hunting

Long legs, sweating ability, endurance running traits.

Reasons to think early Homo may have

Cut marks on bones, stone tools near animal remains, body built for long distance movement.

Carbon isotope analysis of pedogenic carbonates

Soil chemistry used to identify ancient plant types (C3 vs. C4).

Homo rudolfensis

Early Homo species with big brain and a broad, flat face.

The Black Skull

Dark fossil of Paranthropus aethiopicus with strong robust traits.

Turkana Boy

Nearly complete Homo erectus skeleton; shows tall body and long legs.

Dmanisi

Site in Georgia with early Homo fossils showing lots of variation and early migration.

Homo erectus

First fully upright, long-legged human species; first to leave Africa.

Human skin color

Evolved from balancing UV protection and vitamin D needs.

Lice in humans

Their evolution shows when humans lost body hair and when clothing appeared.

Tapeworms

Show humans got parasites by eating meat early in evolution.

The original A. afarensis knee fossil

First strong fossil proof that Lucy's species walked upright.

The Burtele foot

Fossil foot with grasping big toe showing another species still climbed trees.

Features of Australopithecus afarensis that suggest good arboreal capabilities

Curved fingers, long arms, flexible shoulders, and climbing-friendly anatomy.

The new hand of Paranthropus boisei

Shows strong grip muscles, possibly used for tool manipulation.

New ways to determine sex of ancient teeth from enamel

Uses enamel proteins (like amelogenin) to identify male vs. female.