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Unformatted text preview: 1/22/2008 1 BIOL 112 Chapter 24 The Origin of Species What is a Species? The morphological species. The biological species concept reproductive isolation. Practical definition A species is whatever a competent taxonomist says it is. Evolution of New Species How Reproductive Isolation is Maintained Pre zygotic reproductive barriers. Post zygotic reproductive barriers. Pre zygotic Reproductive Barriers Habitat Isolation Behavioral Isolation Temporal Isolation Mechanical Isolation Gametic Isolation Post zygotic Reproductive Barriers Reduced Hybrid Viability Reduced Hybrid Fertility Hybrid Breakdown 1/22/2008 2 Problems With the Biological Species Concept Fossil Species Clonal or Asexual Species Hybridization Cryptic Species Other Species Concepts Morphological Species Concept Ecological Species Concept focuses on role, not phenotype. Phylogenetic Species Concept Modes of Speciation Allopatric Speciation Sympatric Speciation Requirements for Allopatric Speciation A geographical barrier Isolation for long enough to build up differences Requirements for faster speciation A difference in environmental conditions Some genetic difference from parent species...
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This note was uploaded on 06/18/2009 for the course BIOL- 112 taught by Professor Bryanness during the Fall '09 term at Pacific Union.
- Fall '09