The Open Door Web Site : IB Biology : Evolution : The Hominids

SPECIES	CHARACTERISTICS	AGE	ECOLOGY
Pan troglodytes	Cranial capacity: 300 – 400 cm³Knuckle walks and climbs 1^st molar tooth 3 years old Uses simple tools Longevity 40 years	Present day tropical Africa	Omnivore but mainly herbivorous, forest dwelling ape.
Australopithecus afarensis	Cranial capacity: 380 – 450 cm³Height: 1.07m Bipedal (footprints 3.6 Ma old) /climber U-shaped dental arcade but reduced canines	3.9 – 2.9 Ma Ethiopia, Kenya, Tanzania	Arboreal / terrestrial herbivore. Climate starts to change. Antarctic ice cap advance 5 Ma
Australopithecus africanus	Cranial capacity: 500 cm³Bipedal 20 – 35 kg Rounder skull, Parabolic dental arcade Longevity: 40 years maximum	3 – 2.25 Ma Southern and Eastern Africa	Scavenger of bone marrow/brain cases Used simple tools. Cooling of climate reduced rainfall. Further advance of Antarctic ice + appearance of Arctic ice 2.4Ma. Development of scrubland and savannah. Forest cover retreats.
Australopithecus (Paranthropus) robustus	Cranial capacity: 500 cm³Bipedal 40 –70 kg Sexual dimorphism (males twice as bulky as females) Large cheek teeth Heavy muscular skull	2 – 1 Ma S. Africa	Roots and tough fibrous vegetable matter in the diet. Cooling of climate reduced rainfall. Development of scrubland and savannah. Forest retreats.
Homo habilis	Cranial capacity: 600 – 800 cm³Height: 1.20 – 1.35m Simple fashioned tools – choppers (Oldowan culture)	2.6 -1.4 Ma E. Africa	Scavenging
Homo erectus	Cranial capacity: 850 – 1100 cm³Use of fire Height 1.55 to 1.8 m Extended childhood. 1^st molar at 4.6 years old Greater longevity 52 years Speech? Improved tools: Hand axes (Acheulian culture)	1.8 to 0.5 Ma Spread out of Africa (1Ma) throughout the old world	Scavenging to hunting. Use of a home base. 0.9 Ma beginning of the Pleistocene ice age. Oscillations between cold and warm periods.
Homo neanderthalensis	Cranial capacity: 1400 cm³(bigger than H.sapiens) Brow ridge, long low skull Height: 1.67m Stocky build Improved sophisticated tools: sharp flakes produced by a single stroke from a core. (Mousterian culture) sometimes buried their dead Made simple jewellery	250 000 to 28 000 a Europe, Middle East, into Central Asia	Evolved from H. erectus populations perhaps via H. heidelbergensis, then became extinct. Adapted to the ice-age conditions of temperate zone. Large nose may have warmed cold air. The enigma of its extinction is not explained. Theories include failure to adapt to changing climate, replacement by H. sapiens or interbreeding with H. sapiens. DNA evidence seems to rule out the last.
Homo sapiens	Cranial capacity: 1400 cm³ (range 1000 to 2000 cm³) (18% of the body’s energy consumption for 5% of body mass) Speech, Art Extensive tool kit including new materials (bone, ivory, antler) Symbolic thought 1^st molar tooth 5.9 years old Longevity 66 years	From 150 000a to present Originating in Southern Africa and spreading out over the whole world	Omnivore Alters environment Domestication of species, farming. Cooling of the climate during the last glacial period from about 50 000a led to their predominance over other species (e.g. H. neanderthalensis)