Chapter 24 SG - Chapter 24 Speciation- the origin of new...

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Chapter 24 Speciation- the origin of new species; focal point of evolutionary theory since appearance of new species biological diversity Microevolution- evolutionary changes within a population’s gene pool from generation to generation Macroevolution- evolutionary changes above the species level; tracing a new species’ origin and analyzing different branches that developed Anagenesis- aka phyletic evolution, is the accumulation of changes that gradually form given species to new species; “new” species Cladogenesis- aka branching evolution, is the splitting of gene pool into 2+ gene pools giving rise to 1+ new species; promotes bio-diversity Biological Species Concept- (Mayr) species as population(s) whose members can naturally interbreed Prezygotic Barriers- impedes mating or hinders fertilization if mating does occur a. Habitat Isolation- a geographic barrier prevents 2 species from meeting and mating (i.e. water vs. land garter snakes) b. Temporal Isolation- a time barrier prevents 2 species from meet/mating (i.e. seasonal mating of western and eastern skunk) c. Behavioral Isolation- a trait barrier prevents 2 species from meet/mating (i.e. blue-footed boobies’ dances) d. Mechanical Isolation- a structural/morphological barrier prevents “…” (i.e. monkey flower with bee vs. hummingbird pollinator) e. Gametic Isolation- sperm of one species may not be able to fertilize egg of another species (i.e. receptor differences btwn gamete) Postzygotic Barriers- fertilization occurs, but the hybrid zygote may not be viable egg or fertile adult
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This note was uploaded on 08/27/2010 for the course BIO 8432 taught by Professor Lang during the Spring '10 term at Northwestern IA.

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