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V. The Process of Speciation

V. The Process of Speciation. Speciation – formation of a new species. Species – a group of organisms that can breed with one another & produce fertile offspring. *Members of a species can lose the ability to interbreed due to isolation. Isolation – anything preventing

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V. The Process of Speciation

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  1. V. The Process of Speciation Speciation – formation of a new species. Species – a group of organisms that can breed with one another & produce fertile offspring. *Members of a species can lose the ability to interbreed due to isolation. Isolation – anything preventing two groups within a species from interbreeding.

  2. A. Isolating Mechanisms *As new species evolve, populations become reproductively isolated from each other. Reproductive isolation – loss of two groups’ ability to interbreed & produce fertile offspring. -Reproductive isolation can develop through : 1. Behavioral isolation – when two populations are capable of interbreeding but have differences in courtship rituals/other reproductive strategies that involve behavior, ex : Eastern & Western meadowlarks.

  3. Geographic Isolation 2. Geographic isolation – when two populations are separated by geographic barriers such as rivers, mountains, or bodies of water, ex : Abert squirrel & Kaibab squirrel.

  4. Temporal Isolation 3. Temporal isolation – when two or more species reproduce at different times, ex : rainforest orchids.

  5. Processes of Change *Species can also go through the following processes of change : 1. Divergent Evolution 2. Convergent Evolution 3. Coevolution 1. Divergent evolution – when isolated populations of a species evolve independently. -Happens because of geographic barriers or when a small group leaves an original population to colonize a new area. Ex : Brown vs. Polar bears.

  6. Convergent Evolution 2. Convergent evolution – when natural selection produces analogous (similar) adaptations in response to similar environments, ex : Serval cat (Africa) & Maned wolf (SA) - long ears/legs & the same prey.

  7. Coevolution 3. Coevolution – when two or more populations that closely interact over an extended period of time evolve together, ex : flowers & bees.

  8. B. Adaptive Radiation Adaptive radiation – evolution of many diverse species from 1 common ancestor, ex : Darwin’s finches- spread.

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