Transcript Evolution
HSP3U – Unit 1 Click to edit the title text format AnthropologyHuman Evolution Evolutionary Theory •Charles Darwin 1809-1882 •Published Origin of the Species (1859) Islands – observed different species of finches •Galapagos •Controversial ! Darwin’s Theory – Natural Selection •Heritability: Organisms inherit characteristics from their parents 2.Variation: there is a lot of variation within a species 2.Environmental Fitness: Those traits that allow an individual to survive to reproductive age – to pass on to offspring Darwin’s Finches •An example of Variation Peppered Moth UK – example of natural selection •White •Food and Black moths (Variation) source for birds Industrial Rev. most moths – white better camouflaged against white lichen (Enviromental Fitness) •Before Rev – coal dust turned environment black, now black moths better camouflaged. Black moths now surviving to reproduce and pass their colour to next generation (Heritability) •Industrial •Now, most moths are black (natural selection) Evolution – evidence •Physical •Look Anthropologists at: 1. Fossil, bone, stone remains (using dating techniques) 2. Microscopic analysis – pollen, scratches on bone 3. Experiments – flake stone techniques Human Evolution Human Evolution •hominid: is any member of the biological family Hominidae (the "great apes"), including the humans, chimps, bonobos, gorillas and orangutans Hominids Habitual Bipedalism – to habitually walk on two legs. Humans only primate with this adaptation •Bipedalism •What had to happen for us to stand up straight? Bipedalism continued •Structural changes required for us to walk upright: •S-shaped spine •Double arched foot •Pelvis – shorter and wider •More gluteus muscles •Fewer head / neck muscles – therefore a bigger brain Advantages of being bipedal •Free hands for carrying •Can walk longer distances •Can have a continuous good view of surroundings Disadvantages of being bipedal •Highly dangerous birthing process •Offspring very dependent and weak because the skull must grow outside of the womb Hominids and Brain Size •Humans have the largest brain for our body mass compared to other mammals Hominid (human), Primate differences: Primates Social structures Dominance Hierarchies Silverbacks and alpha males in a group Grooming Related to the hierarchies Stress release Hominids / Humans Pair Bonding AND Group Living Humans are the only primates to have both social characteristics simultaneously Hominid (human), Primate differences Primates Reproduction Estrus cycle (in heat) No choice of when to mate Who gets to mate when ties into dominance and grooming hierarchies Hominids / Humans No estrus cycle Choice in when to mate Hominid (human), Primate differences Primates Mother – Infant relationship Long infant dependency compared to other mammals Important in learning survival skills and culture Hominids / Humans Longest infant dependency period of all primates Hominid (human), Primate differences Primates Communication Facial displays, call, touch Hominids / Humans Speech centre in the brain Humanity and our Variations •Our bodies are essentially 50 000 years old. •Now culture, not physical evolution enables us to adapt very quickly to a changing environment - Cultural construct – does not physically exist •Race Skin Colour - Legitimate Explanations for Human Variation •Sunlight is the best source of vitamin D (necessary for healthy bones) •Light skin absorbs vitamin D and burns more easily than darker skin Paler skin is found in areas further from the equator where there is less sunlight (environmental Fitness) •Skin colour (variation) Skin Colour - Legitimate Explanations for Human Variation Darker skin provides better protection from UV rays • •Darker skin is found in areas closer to the equator where there is more and stronger sunlight (environmental Fitness) •Skin colour (variation)