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Unit 8 - Coggle Diagram

- - - - Mutation - change in a DNA sequence, usually occurring because of errors in replication or repair. Mutation is the ultimate source of genetic variation
      - Gene Flow (migration) - the movement of individuals between populations that bring new genetic variation with them
      - Natural Selection - differential survival or reproduction of different genotypes in a population leading to changes in the gene frequencies of a population
      - Genetic Drift - usually happens in small populations, but gene frequencies change as a result of a random occurrence (such as a storm, wildfire, tornado, drought, etc) that wipes out most of the population. Those that remain will have genotypes that may have been different from the original population. So the new population shows a “drift” towards this new gene combination
  - - - Geographical Isolation - assume that some members of a species become geographically separated from the rest of the species. If they remain separated long enough, they may evolve genetic differences. If the differences prevent them from interbreeding with the original species, then they have evolved into a new species
      - Temporal Isolation - assume hawthorn flies lay eggs in Hawthorn trees. THe eggs hatch into larvae that feed on fruits. Apple trees were introduced to the U.S. and are often grown near hawthorn trees. Some hawthorn flies started laying eggs in nearby apple trees. When the eggs hatched, the larvae fed on apples. Overtime, they become reproductively isolated because they breed at different times; the breeding season matches the season when the apple or hawthorn fruits mature. Because they rarely interbreed, the two populations of flies are evolving genetic differences and becoming different species
      - Behavioral Isolation - the blue footed booby has an elaborate mating “dance” that males must do to woo the female. The female can either then accept or reject the advances of the male. Other species of birds do not have the same mating dance and will be fully ignored by the female meaning they have no chance at reproducing with the female blur footed booby.