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Genetic Drift

Genetic Drift. Small populations Definition Genetic bottleneck Founder effect.

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Genetic Drift

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  1. Genetic Drift Small populations Definition Genetic bottleneck Founder effect

  2. You are wandering in the tropical rainforest and a giant bright yellow spider hangs dangling in its web in front of you. How would you determine if you had discovered a new species of spider? If it was a new species of spider, what would you name it?

  3. Why do we classify organisms? • Communication • Problems with common names • Show evolutionary relationship • Systematics • Taxonomy

  4. Scientific Names • 18th century • Latin or Greek • Binomial nomenclature • Linnaeus • 2 word name • Latin • Writing • Italics • First word – Genus • Second word – species • Felis catus

  5. Linnaean Classification • Hierarch ranking system • Taxa (taxon) • Kingdom, phylum, class, order, family, genus, species

  6. Problems with Linnaean Classification • Species are specifically defined • Other groups are subjective • New organisms hard to classify • Eugenics • Classification of humans • Used to justify discrimination

  7. The following is the Linnaean classification of a moose. Match each with the appropriate category name. Hint: they are in order. • alces • Alces • Cervidae • Artiodactyla • Mammalia • Chordata • Animalia

  8. Evolutionary Classification • Darwin’s tree of life • Phylogeny • Group by common ancestors • Clades • Definition • Advantage

  9. Cladograms • Root • Branch • Speciation event • Distances • Patterns based on • Hypotheses • Molecular data • Embryological development • Fossil record

  10. Creating Cladograms • Traits inherited • From common ancestor • Shared by many • Examples • Derived characters • Related to speciation event • Show closeness of common ancestor

  11. Reading Cladograms • Node • Derived characteristics • Last clade

  12. Clades and Linnaeus • Many overlapping groups • Mammalia • Birds very different • Both systems are used

  13. DNA and Classification • Used sequenced genomes • More genes in common • More derived characters in common • More recent common ancestor • Shows relationships that can’t be seen • Examples

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