Sbi3u1 diversity 3 - origins of diversity

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Sbi3u1 diversity 3 - origins of diversity

  1. 1. Origins of Diversity <ul><li>Taxonomy and Evolutionary History </li></ul><ul><li>Cladisitics </li></ul>
  2. 2. Taxonomy Reveals Evolutionary History <ul><li>We cannot use physical characteristics as our sole evidence for evolutionary history </li></ul><ul><ul><li>Ex. Bird wings and insect wings </li></ul></ul><ul><li>Similar traits that evolve independently, such as wings, are the result of convergent evolution </li></ul><ul><li>Features that evolved through convergent evolution are called analogous structures </li></ul>
  3. 3. Taxonomy Reveals Evolutionary History <ul><li>Similar features that are the result of a common evolutionary ancestry are called homologous structures </li></ul><ul><ul><li>Ex. The arm bones of an ape and a human </li></ul></ul><ul><li>The evolutionary history of a species is called its phlogeny </li></ul>
  4. 4. Cladistics <ul><li>Cladistics is a branch of taxonomy that investigates and illustrates phylogenies based on several types of evidence </li></ul><ul><ul><li>Physical evidence </li></ul></ul><ul><ul><li>Genetic evidence </li></ul></ul><ul><ul><li>Molecular evidence </li></ul></ul><ul><ul><li>Embryological evidence </li></ul></ul>
  5. 5. Cladogram <ul><li>Cladograms are diagrams that are used to illustrate the addition of derived traits , or traits that are unique within the group. It is supposed that the more derived traits a species has, the further it is in the evolutionary history </li></ul>
  6. 6. Cladogram
  7. 7. Phylogenetic Trees <ul><li>Cladograms are simplistic in that they don't consider the importance of each trait </li></ul><ul><li>When more information is available a phylogenetic tree can be a more accurate depiction of evolutionary histories </li></ul>

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