lecture 30 notes.docx

Introduction to Human Evolution Lecture 30 notes Monday, November 27th The Evolution of Homo in the Pliocene and Pleistocene (both important) Origin and evolution of our species related to climate change Cyclic glaciation began 3 mya and increased throughout the Pleistocene (2.6 mya — 11,600 ya) A...

Introduction to Human Evolution Lecture 30 notes Monday, November 27th The Evolution of Homo in the Pliocene and Pleistocene (both important) Origin and evolution of our species related to climate change Cyclic glaciation began 3 mya and increased throughout the Pleistocene (2.6 mya — 11,600 ya) About 2.5 mya, sea levels lowered so that island Southeast Asia connects to mainland Asia we know that when we think of early primate evolution, there were land bridges, the same thing applies later in time and we see these shifts The Pleistocene The Pleistocene, often called the ice age, was marked by advances and retreats of massive continental glaciations at least 15 major and 50 minor glacial advances have been documented in Europe Hominins were impacted as the climate, flora, and animal life shifted interconnectedness within individuals and the land that make up a given ecosystem Middle Pleistocene The portion of the Pleistocene epoch beginning 780,000 ya and ending 125,000 ya Late Pleistocene The portion of the Pleistocene epoch beginning 125,000 ya and ending approximately 10,000 ya Glaciation Climactic intervals when continental ice sheets cover much of the northern continents Glaciations are associated with colder temperatures in northern latitudes and more arid conditions in southern latitudes, most notably Africa Tropical and warm exhibit certain features, that allowed them to survive over other Homo erectus as a hallmark species that gave rise to our lineage, it’s important to understand why we see so many changes in different parts of the world Interglacials Climactic intervals when continental ice sheets are retreating, eventually becoming much reduced in size Interglacials in northern latitudes are associated with warmer temperatures, while in southern latitudes the climate becomes wetter Dispersal of Middle Pleistocene Hominins Europe becomes more permanently and densely occupied Mostly remained in areas previously occupied by Homo erectus (first to leave Africa, migrate out and populate different locations— but then we see these transitions from h.erectus through out time, during its 2mya of existence, we see changes and modifications of traits and seeing the emergence of other species, perhaps co-existing more mixing between, genetic mutations can arise (only thing that can introduce new alleles into a population) The Dmansis Hominin Dmanisi Fossils - from the Republic of Georgia ~1.8 mya First evidence of leaving Africa Several stone tools, similar to Oldowan tools from Africa; evidence of advances social behavior (loss of teeth but still survived) Found without teeth and evidence shows they lived without teeth, evidence indicating they were taken care of First time evidence of culture and social behavior; notions of altruism, selflessness without anything in return, for the sake of another individual Significant because 1.8 mya showing the earliest emergences of social bonds and the roots of human behavior Shorter stature than later H. erectus specimens from East Africa or Asia Homo Heidelbergensis Middle Pleistocene: 600-200 kyr Homo Erectus around the world Africa 1.8-1.9 mya Georgia: 1.7 mya SE Asia 1.8 mya (indonesia, the islands) Continental Asia: 8,000 ya Western Europe: fossils belong to a different lineage Technological Trends in Homo erectus Expansion of the brain enabled H. erectus to develop sophisticated tools that span two stone tool industries: Oldowan and Acheulean Acheulian: biface, stone worked on both sides and used to cut, scrape, pound, and dig (hand axe or cleaver)