Lesson 4

The evolutionary process that led from early hominoids to modern Homo sapiens, including anatomical, cognitive, and cultural changes.

In Africa ≈ 30–25 million years ago; later diversified across Africa, Europe, and Asia.

No tail,

bunodont molars (five low rounded cusps),

small brain (~300 cc),

arboreal,

brachiation/knuckle-walking,

strong sexual dimorphism,

and opposable thumb.

Miocene apes

• (≈ 17–9 MYA)

• that spread to Europe & Asia (e.g. Pierolapithecus, Hispanopithecus, Sivapithecus);

• ancestral to African apes and humans.

Divergent evolution of primitive hominoids in isolated African regions

→ lineages of great apes and humans; first bipedal forms appear.

Forward (advanced) foramen magnum,

S-shaped spine,

broad pelvis,

knees under body,

big toe aligned with others.

Energy efficiency

, higher field of vision,

better thermoregulation,

frees hands for carrying / tool use,

enables vocalization and speech.

Slower movement → greater vulnerability to predators and competition for food.

• Sahelanthropus tchadensis (7 MYA),

• Orrorin tugenensis (6 MYA),

• Ardipithecus kadabba & ramidus (5.8–4.1 MYA).→ Small brains (~300 cc), partly bipedal, arboreal traits.

≈ 4.4 MYA, Aramis (Ethiopia);

• height ~1.2 m, weight ~50 kg,

• cranial capacity ≈ 300 cc;

• facultative biped.

• African hominins (4.2–1.8 MYA)

• showing habitual bipedalism and small brains (380–450 cc).→ Divided into gracile (A. afarensis, A. africanus, A. garhi, A. sediba) and robust (Paranthropus) species.

“Lucy” (3.8–3 MYA, Ethiopia) — partial skeleton showing clear bipedalism; footprints at Laetoli (Tanzania, 3.5 MYA).

Brain 380–450 cc; large jaws & teeth; vegetarian diet; bipedal + arboreal; strong sexual dimorphism.

Specialized for chewing hard foods (tubers / roots): sagittal crest, thick enamel, massive jaws, large molars; brain similar to Australopithecus.

≈ 3.3 MYA (Lomekwi 3, Kenya); crude tools, possibly used by Australopithecus garhi (2.5 MYA).

Homo habilis (≈ 2.1–1.45 MYA):

• brain ≈ 550 cc; smaller teeth / jaws;

• omnivorous diet; Oldowan stone tools.

Systematic tool making

(Oldowan industry: hammerstones, choppers, flakes) → meat consumption via scavenging.

Homo ergaster (= Homo erectus)

≈ 1.8 MYA; brain 800–1100 cc,

height 1.8 m,

less prognathism,

smaller teeth,

efficient biped.

First to leave Africa;

Acheulean tools (hand-axes);

organized hunting;

use of fire;

cooperative life.

Protection, warmth, cooking (better digestion & taste), insect repellent, food preservation, directing prey, longer activity time.

Homo erectus and its relatives (H. georgicus, H. cepranensis, H. antecessor, H. floresiensis).

“the Hobbit” (Flores Island, Indonesia) — height 1 m, brain 380 cc, lived ~18 000 years ago; case of insular dwarfism.

A small-brained (465–610 cc) Homo from South Africa (~300 000 years ago); mosaic of primitive and modern traits.

600 000–200 000 years ago;

Africa & Europe;

larger brain,

still pronounced brow ridges;

ancestor of Neanderthals and modern humans.

1️⃣ Denisovans

2️⃣ Neanderthals (H. neanderthalensis)

3️⃣ Archaic H. sapiens — all from a shared maternal ancestor (mtDNA).

Brain ≈ 1 400 cc;

robust body;

short limbs;

large nose;

skilled hunters;

Mousterian tools;

symbolic burials;

survived until ≈ 27 000 years ago.

1–4 % of European Homo sapiens DNA originates from Neanderthals (interbreeding confirmed).

A distinct human lineage identified by DNA (Siberia, ≈ 40 000 years ago);

hybridized with both Neanderthals and H. sapiens.

≈ 300 000 years ago (Jebel Irhoud, Morocco); brain 1 350 cc; flat face, chin, slender build.

• Symbolic art,

• language,

• diverse tools (microlithic),

• complex social organization,

• global dispersal.

• Left Africa ≈ 110 000 years ago;

• reached Australia ~50 000 years ago,

• and the Americas ~15 000 years ago.

• Evolved from gestures + vocalizations;

• anatomical changes (larynx descent, Broca’s area, FOXP2 gene mutations) enabled articulate speech.

FOXP2 — regulates other genes for brain and vocal control;

in H. sapiens it has two mutations enabling speech.

• Bipedalism

• • Tool use

• • Omnivorous diet

• • Encephalization

• • Control of fire •

• Permanent camps •

• Social organization •

• Language

• • Art