Wk 6 Lec 2s

Wk 6 Lec 2s - Chapter14 Howbiologicaldiversityevolves

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Chapter 14 How biological diversity evolves
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Macroevolution and the Diversity of Life Macroevolution Encompasses the major biological  changes  evident in the fossil record . Includes the formation of new species. Speciation The focal point of macroevolution. May occur based on two contrasting  patterns. In  non-branching evolution , a population  transforms but does not create a new  species. In  branching evolution , one or more new  species branch from a parent species that  may continue to exist.
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The Origin of Species Species is a Latin word meaning “kind” or “appearance.” What Is a Species? The  biological species concept  defines a species as a population or group of  populations whose members have  the potential to interbreed and produce  fertile offspring . The biological species concept  cannot  be applied in all situations, for  example, with  fossils and asexual organisms .
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Reproductive Barriers between Species Prezygotic barriers prevent mating  between species . Prezygotic barriers include Temporal  isolation. Habitat  isolation. Mechanical  isolation. Gametic  isolation. Behavioral  isolation
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Reproductive Barriers between Species Postzygotic barriers  are  mechanisms  that operate  should  interspecies mating   actually occur and form  hybrid zygotes. Postzygotic barriers include Hybrid inviability. Hybrid sterility .
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A key event in the potential  origin of a species occurs when  a population is somehow  severed from other populations  of the parent species . The two modes of speciation 
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Wk 6 Lec 2s - Chapter14 Howbiologicaldiversityevolves

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