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Learning Target : Evidence of Evolution. I Can … Describe reasons that provide evidence that evolution occurred throughout the past I Will … Explain and give examples of evolutionary evidence from: Fossil record Biogeography Embryology Anatomy Homologous structures Analogous structures
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Learning Target: Evidence of Evolution • I Can… Describe reasons that provide evidence that evolution occurred throughout the past • I Will… • Explain and give examples of evolutionary evidence from: • Fossil record • Biogeography • Embryology • Anatomy • Homologous structures • Analogous structures • Vestigial structures
Evidence of Evolution: Natural Selection • Natural Selection – Mechanism of how evolution (genetic change over time of a population) happens. • Genetic variation • Selective pressure • Environment • Adaptation (advantage for survival and/or reproduction) • Right before our eyes • Dog breeds • Antibiotic resistant bacteria • Peppered moths • But, life has been around for a very long time
Evidence of Evolution: Fossil Record • Fossil – traces of organisms that existed in the past mineralized over time • “Rock snapshot of organisms in the past” • Fossil records shows: • Types of organisms • Structure of the organism • Location, ecosystem they lived in • Age (when they lived) • Rock layers • Deeper = older • Radioisotope dating of surroundings • Organisms that have become extinct • Changes in populations over time
Evidence of Evolution: Geography • Biogeography – study of the distribution of organism around the world • Organisms from different areas show similarities • Past migration from common population • New ecosystems exert selective pressure • Adaptations over time • Geography can isolate groups • Prevents mating between separated groups • Galapagos Finches
Evidence of Evolution: Geography • Galapagos Finches:
Evidence of Evolution: Embryology • Embryology – Comparative anatomy study of embryo stage of development in organisms • Different looking adults can have very similar embryo stage • Fish, birds, reptiles, mammals • All have gill slits in embryo stage • Develops into throat and ear structures in mammals • Strong evidence of common ancestor
Evidence of Evolution: Anatomy • Anatomy – study of structure • Homologous structures • Similar structures with different function • Result of selective pressure • Strong evidence of common ancestor
Evidence of Evolution: Anatomy Homologous Common Tetrapod Ancestor
Evidence of Evolution: Anatomy Analogous • Analogous structures – • Different structures with similar function • Selective pressure, such as need for flight, forced similar traits in different organisms
Evidence of Evolution: Anatomy Analogous Homologous structures Analogous structures
Evidence of Evolution: Anatomy Vestigial • Vestigial structures – • Remnants of organs or structures that had a function in an ancestor, but no longer function in present day descendants • Very strong evidence for evolution and change over time as selective pressures change
Evidence of Evolution: Anatomy Vestigial Snakes – Also had a common tetrapod ancestor