Hominization, Lucy and Miocene apes

The human lineage is a bush. Linear charts are teaching lies.

• Becoming hominin: bipedalism, non-honing chewing (reduced canines), tools and later culture — a bundle, not one switch.
• Skeletal flags: valgus knee, S-spine, anterior foramen magnum, platform foot, non-opposable hallux, later chin and smaller jaws with softer diets.
• Bipedalism models (foraging, display, carrying, thermoregulation, walking efficiency) — pick two and cost the rest (varicose veins, childbirth, back pain).

• Sahelanthropus tchadensis (Chad, ~7–6 mya, Brunet): anterior foramen magnum, small non-honing canines — possible early biped.
• Orrorin: femoral cortex as weight-bearing hint.
• Australopithecus: Africa, 400–600 cc, habitual bipeds, big teeth. Gracile (afarensis, africanus, sediba…) vs robust Paranthropus (sagittal crest, megadont).
• Lucy (A. afarensis, Johanson, Afar, ~3.6–2.9 mya) and Dikika child: biped with climbing fingers; strong dimorphism.
• Robust extinction: overspecialised diet plus Homo competition is the usual story.

• Proconsul (Africa): early ape, no tail. Dryopithecus (Europe): more suspensory.
• Sivapithecus / Ramapithecus: once sold as the first human; now orangutan-line, Ramapithecus often the female morph — not a hominin ancestor.