Geological Evolution • Plate tectonics or Continental Drift Theory states… Earth’s surface is divided into plates that continually move, taking the continents with them Types of plate boundaries: Convergent: plates come together often forms mountain chains Divergent: plates separate causing faults (earthquake)
History of Plate Tectonicshttp://pubs.usgs.gov/gip/dynamic/historical.html Pangaea: 225 MYA- one super continent Laurasia & Gonwanaland: 200 MYA- Pangaea separated into 2 continents Today: 7 major continents due to plate movement Evidence: Polar Dinosaur Cryolophosaurus ellioti: fossils found in S. Australia and in Antarctica
How does this relate to Life Science? • Climates change as… • Land moves away from equator • Land moves toward equator • Oceans/Seas disappear or appear • Mountain ranges form • New coastlines form • Biomes Change meaning… • Organisms must adapt to these changes • Beneficial adaptations will be passed on in successive generations thus changing the source of genes (natural selection) Animals of the Taiga
Evolution Clues • Homologous structures: body structures of different organisms that are similar in origin and structure • Forelimbs of chordate animals (animals w/ backbones) • http://evolution.berkeley.edu/evolibrary/article/similarity_ms_01 Questions: • How are tetrapods’ limbs similar? • What is an example of a plant homology? • What is an analogous structure? • Why might some structures evolve independently in various organisms? • Other Evidence: • Vestigial Structures: structures that have no known function • In humans: tail bone and muscles around the ear • Similar DNA: organisms of the same species generally share 99 - 99.9% same DNA • Various Primates of different species all share a common ancestor
Trends in Evolution • http://evolution.berkeley.edu/evosite/evo101/VIIDTrends.shtml • How do complex structures like eyes evolve? http://evolution.berkeley.edu/evosite/evo101/VIICComplexity.shtml • What is a transitional form? http://evolution.berkeley.edu/evosite/lines/IAtransitional.shtml • What is “evolutionary opportunity”? ex. Dinosaur extinction leads to a rise in mammal species on Earth So scientists hypothesize that what has occurred in nature in the past will continue to occur into the future and can help us predict what the future life on Earth will be like… How WILD will that future be?????