Chapter 24

Chapter 24 - Chapter 24 The Origin of Species January 25,...

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Chapter 24 The Origin of Species – January 25, 2008 1) Speciation a) Anagenesis: accumulation of heritable changes, altering the characteristics of a species b) Cladogenesis: new species arise from a population being insolated from the parent species 2) The biological species concept emphasizes reproductive isolation a) Species: Latin for “kind” or “appearance” 3) The Biological Species Concept a) Defines a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring b) Cannot be applied to i) Asexual organisms ii) Fossils iii) Organisms about which little is known regarding their reproduction c) Speciation is dependent on reproductive isolation and genetic divergence 4) Reproductive Isolation a) The existence of biological factors that impede members of two species from producing viable, fertile offspring b) Prezygotic barriers c) Postzygotic barrier 5) Prezygotic barriers a) Impede mating between species or hinder the fertilization of ova if members of
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This note was uploaded on 02/04/2009 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Chapter 24 - Chapter 24 The Origin of Species January 25,...

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