Chapter 24Speciation- the origin of new species; focal point of evolutionary theory since appearance of new speciesbiological diversityMicroevolution- evolutionary changes within a population’s gene pool from generation to generationMacroevolution- evolutionary changes above the species level; tracing a new species’ origin and analyzing different branches that developedAnagenesis- aka phyleticevolution, is the accumulation of changes that gradually form given species to new species; “new” speciesCladogenesis- aka branching evolution, is the splitting of gene pool into 2+ gene pools giving rise to 1+ new species; promotes bio-diversityBiological Species Concept- (Mayr) species as population(s) whose members can naturally interbreedto produce viable & fertile offspringReproductive Isolation- existing biological factors/barriers that impede members of two species from making viable & fertile hybridsPrezygotic Barriers- impedes mating or hinders fertilization if mating does occura.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)
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