Human Evolution: A Journey Through Time
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| Species | Time Period (mya) | Cranial Capacity (cc) | Geographic Distribution | Key Features and Notes |
|---|---|---|---|---|
| Homo habilis | 2.4-1.4 (2.8) | >600 | Olduvai Gorge (Tanzania), Turkana/Baringo Basin (Kenya), Omo/Hadar (Ethiopia), Sterkfontein/Swartkrans (South Africa) | Type: OH 7, KNM-ER 1813. Primitive limb proportions, small, dark supraorbital torus and sulcus, almost orthognathic, small parabolic maxilla, small zygomatics, small teeth. Primitive postcrania, long arms and short legs, slightly curved phalanges. Generally smaller morph. |
| Homo rudolfensis | 2.0-1.8 | 750 | Turkana (Kenya), Omo (Ethiopia) | Lectotype: KNM-ER 1470. Flatter, wider face, larger teeth, no sulcus, small supraorbital torus. More derived postcrania. Generally larger morph. |
| Homo erectus | 1.9-0.4 | 1000+ | Africa, China, India, Georgia. Turkana Basin (Kenya) = oldest. | Type: Dubois' original skullcap from Trinil. African: Smaller supraorbital sulcus, rounded occipital, no/small sagittal keel, double brow ridge. Asian: Pointed occipital, large sagittal keel, large sulcus, shelf-like brow ridge. Gracile teeth/jaw, modern postcrania, Homo sapiens-like life history. Turkana Boy/KNM-WT 15000 represents a shift towards derived features from earlier hominins. |
| Homo antecessor | 1.2-0.8 | N/A | Atapuerca (Spain), Sima del Elefante (1.2 mya), Gran Dolina (0.95-0.8 mya) | Type: ATD6-5 mandible. First European hominin, 'advanced' Homo erectus. Slender maxilla, no midface projection, canine fossa. Clear evidence of cannibalism, reasons unknown. |
| Homo heidelbergensis | 0.8-0.2 | 1200 | Africa, Europe, Asia. Heidelberg (Germany), Bodo (Ethiopia), Kabwe/Broken Hill (Zambia), Petralona (Greece), Spain. | 'Archaic hominins'. Type: Mauer Mandible. Heavily built with large face, double brow ridge, no/very slanted forehead, more rounded skull, occipital torus, pentagonal skull shape. Intermediate between H. sapiens and H. erectus. Sima de los Huesos: Minimum number of individuals = 28. First active hunters. |
| Homo neanderthalensis | 0.2-0.035 | 1450 | Europe, West Asia, and the Levant. Neander Tal (Germany), La Chapelle-aux-Saints (France), Shanidar (Iraq), Kebara (Israel). | Type: Feldhofer 1 skullcap. Postcrania: Cold-adapted, complex and advanced culture. 35% stronger than humans of the same size. More projecting face, lower and longer skull, occipital bun, large brow ridge, large eye and nose openings, small mastoid process, extremely worn anterior teeth, faster life history (fully grown by 15, dead by 40-45), frequent serious injuries. Levallois/Mousterian/Châtelperronian tool cultures. Disappeared around 30-35 kya, reasons unknown. |
| Homo denisova | 0.16-0.04 | N/A | Siberia and China | Described from very few remains and genetic data. Interbred with Neanderthals and H. sapiens (Oceania). Larger molars (within Pliocene range), very thick crania. |
| Homo floresiensis/luzonensis | 0.1-0.06 | 400 | Island of Flores (Indonesia) and Luzon Island (Philippines) | Short stature (110 cm), mosaic postcrania, culture similar to H. erectus. Homo in the region for 1 million years. Islands isolated by ocean currents. Low and long skull, small forehead, double brow ridge, thick and receding symphysis, relatively large teeth. Long arms/short legs, primitive humerus, Australopithecus-like pelvis, primitive carpals, very long feet with primitive arch. Insular dwarfism. H. luzonensis: Even smaller teeth, fewer samples, curved phalanges. |
| Homo naledi | 0.335 | 460-610 | Rising Star Cave (South Africa) | Type: Dinaledi male cranium. Small brain (similar to Australopithecus), primitive postcrania, derived wrist and thumbs, long and curved fingers, derived ankle and tarsals, primitive arches, high and thin skull, fits Homo habilis features. |
| Homo sapiens | 0.2-present | 1350 | Originated in Africa, widespread in East and South Africa by 120 kya, Levant by 110-100 kya, Romania by 42 kya. | Type: Carl Linnaeus. Defining features: Chin, canine fossa, distinct forehead, globular skull. H. sapiens postcrania, large mastoid process, most gracile hominin, unique dentition, H. sapiens life history. |
Out of Africa Model: 1.8 mya H. erectus migrated out of Africa. 100 kya H. sapiens migrated out of Africa and completely replaced other hominins without interbreeding.
Multiregional Evolution Model: Continuous gene flow across all populations in all regions. H. erectus migrated out of Africa and beyond, and gene flow (even if sporadic) kept all populations as the same species as they evolved into H. sapiens.
Assimilation Model: 1.8 mya H. erectus migrated out of Africa. 100 kya H. sapiens migrated out of Africa, and genes were exchanged, with archaic species being assimilated.
Assimilation Model Predictions: 1. Most genetic variation within populations. 2. Shallow genetic roots. 3. H. sapiens in Africa first. 4. Evidence of interbreeding. 5. H. sapiens originating in Africa, then spreading elsewhere. (All of these are evident, which is why this model is most supported by archaeological, genetic, and fossil evidence.)
Anatomically modern human behavior was not sudden. Technological innovations appeared first in Africa and spread outward, making the appearance of change seem sudden, but it was not. There was a gradual increase in behavioral modernity over 200,000 years.
Nuclear DNA shows Neanderthal interbreeding, but mitochondrial DNA does not (for various reasons). A typical non-African descendant has 1-3% Neanderthal DNA.
Possible reasons for Neanderthal extinction: Genocide, competition, climate change, cultural inferiority, demographics, or disease.
