Chapter 13 T9 – Chapter 14 T1

Chapter 13 T9 – Chapter 14 T1 - histories o...

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Chapter 13 T9 – Chapter 14 T1-T2 28/01/2008 10:01:00 Topic #9 Notes on Variation Source of Variation – mutation Major increase in variation – recombination o Not only unique because of different alleles, but also have different  combinations of alleles o Crossing over (meiosis) o Random assortment o Random fertilization (sex) o How does generation time effect evolution (accumulation of variation)? The shorter the generation time = the faster variation  accumulation (evolution) Origin of Species : Chapter 14 The perfect organism? Species Concepts Speciation Reproductive Isolation Tempo of Evolution Topic #1 The Perfect Organisms? Natural Selection can not produce perfection o Evolutionary (historical) constraints Tinker with old design rather than start from scratch
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Example – stingrays and founders Similar strategy – different method based on different 
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Unformatted text preview: histories o Adaptations are often compromises Walking vs. Swimming – seals o Not all evolution is adaptive Genetic drift is more frequent than often thought o Selection can only edit existing traits Even artificial selection Topic #2 Species Concepts • What is a species? o Biological species concept = group of actually or potentially interbreeding individuals that are reproductively isolated from other such groups Advantages Definable Disadvantages Asexual organisms? Reproductive isolation can not be determined in all cases (fossils) o Phylogenetic species concept – defined by reconstructing phylogeny. Species is an independently evolved lineage Advantages Includes asexual organisms Disadvantages Clades are hypothesis Somewhat subjective 28/01/2008 10:01:00 ← 28/01/2008 10:01:00 ←...
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This note was uploaded on 10/21/2008 for the course BIOL 1301 taught by Professor Harbison during the Spring '08 term at University of Texas-Tyler.

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Chapter 13 T9 – Chapter 14 T1 - histories o...

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