Tracing the Path of Human Development Lesson ObjectiveAnalyze hominin evolutionLesson Key ConceptsHomo erectus: a hominin species that lived between 1.8 million and 25 thousand years agoHomo heidelbergensis: a hominin species that lived between 850,000 and 125,000 years agoHomo neanderthalensis: a hominin species that lived between 130,000 and 10,000 years agoHomo sapiens: modern humans, which evolved around 195,000 years ago and are still alive todayBrowridge:a projection of bone above the eyesNuchal torus: the part of the back of the skull where neck muscles attachAcheulian: the stone tool industry developed by Homo erectusBiface: a stone tool used like a hand axe, which could be used to cut, scrape, pound, and digComplete replacement model: Homo sapiensfrom Africa replaced all other hominin species around the worldVocabulary WordsProjecting: sticking outEmigrate: to leave one’s place of residence or country to live elsewhereAnatomy: the structural makeup of an organismElaborate: complex, detailed, intricateThe Stages of Hominin DevelopmentAfter hominin evolution had brought about the earlyHomoin Africa, our ancestors’ further development started moving quickly. Evolutionary forces continued to work on hominins. Early Homo hominins began to take
on somewhat more modern characteristics. This began to happen around two million years ago. Many of the hominin fossils that anthropologists havefound from that time and later have shown fewer differences than older fossils did. (Australopithecines were still alive at this point, but our Homo ancestors were evolving away from them.) However, the transition from early Homoto Homo sapienstook a very long time. Different forms of hominins evolved during that time.Four Main Hominin Species within the Genus HomoNameTime ExistedCharacteristicsHomo erectusLived between 1.8 million and 25 thousand years agoAverage brain size of 930 cm3, large face, thick skull, large browridges, and a receding foreheadHomo heidelbergensisLived between 850,000 and 125,000 years agoAverage brain size of 1,200 cm3, large browridges, low forehead, and a long headHomo neanderthalensisLived between 130,000 and 10,000 years agoAverage brain size of 1,450 cm3, long and low head, large browridges, weak chin, and a protruding midfacial areaHomo sapiens(or modern humans)Evolved around 195,000 years agoAverage brain size of 1,325 cm3, high forehead, small brow ridges,and a prominent chinIf we could watch the evolutionary progress of these hominins, it would be amazing to see them become more and more like us! Well, while we can’t actually see this happen, we can study it through the fossil record. That is what countless anthropologists have done, and that’s what we’re about to do! We’ll start with the first species of the more modern hominins: Homo erectus.
Homo ErectusThe fossil record indicates that Homo erectus(which literally means "upright man") first appeared 1.8 million years ago. Like other hominins before it, H. erectusoriginated in Africa. The oldest fossil remains of H.