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Agenda

Agenda. 15 minutes to finish – focus on the PopG part, finish graphing/questions on your own Microevolution Time to work on HW HW: Microevolution Worksheet Short Quiz Friday. Microevolution. Small Changes Over Time. Two Ways to Look At Evolution. Microevolution. Macroevolution.

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Agenda

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  1. Agenda • 15 minutes to finish – focus on the PopG part, finish graphing/questions on your own • Microevolution • Time to work on HW • HW: Microevolution Worksheet • Short Quiz Friday

  2. Microevolution Small Changes Over Time

  3. Two Ways to Look At Evolution Microevolution Macroevolution The formation of new species or taxonomic groups How did animals evolve, how did mammals evolve etc. • Changes in a gene pool of a population • E.g. a population accumulating longer neck genes, darker fur genes

  4. Computer Models • Demonstrate microevolution • Allows us to isolate one variable and examine its effects

  5. What Causes Evolution? • Mainly Natural Selection • Even slight advantages cause a change in the gene pool

  6. Migration aka Gene Flow • An individual can bring genes from one population to another, which changes the population

  7. Random Chance (Genetic Drift) • In small populations, pure chance may cause microevolution • Small islands tend to have lots of diverse species

  8. Small Populations • Any situation that leads to small populations can lead to genetic drift • e.g. a small group colonizing a new island • e.g. a large disaster leaving only a few survivors

  9. Mutations • Errors when DNA is copied lead to new genes • They change the gene pool or the collection of all the genes

  10. Sexual Selection • Traits that help individuals find a mate can become common – even if they decrease the chances of survival http://www.youtube.com/watch?v=7dx2CUMtZ-0

  11. Usually Female Choice • Females choose which traits they like • These traits then become more and more common over time • Can lead to males looking very different than females

  12. Hardy-Weinberg Equilibrium For a population to NOT evolve, or be in equilibrium, a population must • Be Large • Be Isolated • Randomly Mate • Have all individuals have an equal chance of survival • Have no mutations

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