What are the four modes of evolution?
Mutation <ul><li>Provides new alleles, and therefore are the ultimate source of variation.  </li></ul><ul><li>Is an change...
Examples of Mutation
Migration <ul><li>Enables  gene flow : the movement of genes from one population into another.  </li></ul><ul><li>Continue...
Example of Migration <ul><li>Some beetles with brown genes immigrated from another population, or some beetles carrying gr...
Natural Selection <ul><li>Is the process that results in adaptation of a population to the environment.   </li></ul><ul><l...
Natural Selection <ul><li>Natural Selection enables beneficial mutations to be passed on to the next generation.  </li></u...
Example of Natural Selection <ul><li>Beetles with brown genes escaped predation and survived to reproduce more frequently ...
Genetic Drift <ul><li>In each generation, some individuals may, just by chance, leave behind a few more descendents (and  ...
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Mechanisms of evolution_basic

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Mechanisms of evolution_basic

  1. 1. What are the four modes of evolution?
  2. 2. Mutation <ul><li>Provides new alleles, and therefore are the ultimate source of variation. </li></ul><ul><li>Is an change in the DNA nucleotide sequence of an allele. </li></ul><ul><li>May not immediately affect the phenotype. </li></ul><ul><li>Can be beneficial, neutral, or harmful </li></ul>
  3. 3. Examples of Mutation
  4. 4. Migration <ul><li>Enables gene flow : the movement of genes from one population into another. </li></ul><ul><li>Continued gene flow decreases diversity among populations, causing gene pools to become similar </li></ul>
  5. 5. Example of Migration <ul><li>Some beetles with brown genes immigrated from another population, or some beetles carrying green genes emigrated. </li></ul>
  6. 6. Natural Selection <ul><li>Is the process that results in adaptation of a population to the environment. </li></ul><ul><li>Natural selection requires: </li></ul><ul><ul><li>variation             </li></ul></ul><ul><ul><li>inheritance             </li></ul></ul><ul><ul><li>differential adaptedness </li></ul></ul><ul><ul><li>differential reproduction </li></ul></ul>
  7. 7. Natural Selection <ul><li>Natural Selection enables beneficial mutations to be passed on to the next generation. </li></ul><ul><li>These beneficial mutations are called ADAPTATIONS </li></ul>
  8. 8. Example of Natural Selection <ul><li>Beetles with brown genes escaped predation and survived to reproduce more frequently than beetles with green genes, so that more brown genes got into the next generation </li></ul>
  9. 9. Genetic Drift <ul><li>In each generation, some individuals may, just by chance, leave behind a few more descendents (and genes , of course!) than other individuals. The genes of the next generation will be the genes of the “lucky” individuals, not necessarily the healthier or “better” individuals. </li></ul>

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