Speciation: Creation of Different Species

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SpeciationCreation of Different Species
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• Evolution by the process of natural selection
  eventually leads to speciation.
• Speciation formation of a new species

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• Species
• A group of similar organisms that can
  inter-breed and produce fertile offspring
• Members of same species share a common gene pool

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• Speciation occurs when a common group of
  organisms becomes two or more separate groups
• New group(s) are reproductively isolated

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• 3 mechanisms of Reproductive isolation
• Geographical
• Behavioral
• Temporal

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• Geographical- populations are separated by
  physical barriers.
• Rivers
• Mountains
• Bodies of water

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• Behavioral- Different courtship rituals
• Mating songs
• Mating dances

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• Temporal (time) Populations mate at different
  times
• Spring vs Fall
• Night vs Day
• Lunar cycle

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• Speciation can occur quickly or slowly
• 1. Gradualism evolution occurs at a slow, steady
  rate
• 2. Punctuated equilibrium- evolution occurs
  relatively quickly (10,000 years or less) in
  rapid bursts
• What do you think the fossil record would look
  like for these two types of speciation?

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Patterns of Evolution

• 1. Adaptive radiation
• An ancestral species evolves into several
  species in order to fit diverse habitats.
  Frequently seen on island chains (hint)- Where
  have you seen this?

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Darwins Finches
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• 2. Convergent evolution
• Two unrelated species in two different parts of
  the world develop similar features.
• Why would two unrelated species of plant or fish
  look so much alike?

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Organ pipe cactus (l) and Euphorbia (R) fleshy
bodies, no leaves