BIO121ch20

BIO121ch20 - BIO121 I. Chapter 20 (Speciation and Macro...

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BIO121 I. Chapter 20 (Speciation and Macro Evolution) A. Biological Species Concept A.1. Species A.1.a) One or more populations A.1.b) Members interbreed in nature A.1.c) Produce fertile offspring A.1.d) Do not interbreed with different species. A.2. Problems A.2.a) Biological species concept applies only to sexually reproducing organisms A.2.b) Individuals assigned to different species may occasionally successfully interbreed A.2.c) Chronospecies - looking at things in the fossil records. A.2.d) Ring Species - the kind of thing that happens when you have a population or species that spreads out from where it originally was, can spread out long distance. You have changes along that path of dispersion. A.3. According to the biological species concept, a species consists of individuals that can successfully reproduce with one another. B. Reproductive Isolating Mechanisms B.1. Restrict gene flow between species B.2. Pre-zygotic barriers B.2.a) Prevent fertilization from taking place. B.3. Post-zygotic barriers B.3.a) Prevent gene flow after fertilization has taken place (reproductive isolating mechanisms) B.4. Pre-zygotic Barriers (1) B.4.a) Temporal Isolation (B.4.a.1) Two species reproduce at different times of day, season, or year. B.4.b) Habitat Isolation (B.4.b.1) Two closely related species live and breed in different habitats in same geographic area. B.5. Pre-Zygotic Barriers (2) B.5.a) Behavioral Isolation (B.5.a.1) Distinctive courtship behaviors preventing mating between species B.5.b) Mechanical Isolation (B.5.b.1) Incompatible structural differences in reproductive organs of similar ??? B.6.
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This note was uploaded on 02/21/2012 for the course BIO 121 taught by Professor Druger during the Fall '05 term at Syracuse.

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BIO121ch20 - BIO121 I. Chapter 20 (Speciation and Macro...

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