Lec 3 Bild 3 2011 for Ted(1)

Lec 3 Bild 3 2011 for Ted(1) - BILD 3 Lecture 3: Natural...

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BILD 3 Lecture 3: Natural Selection I. Background II. Artificial selection III. Variation IV. Measuring evolution by natural selection V. Modes of selection
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I. Background Phenotype : the characteristics of an organism as a result of genes and the environment Genotype : genetic composition of an organism Phenotype: Blue Eyes Genotype: bb Phenotype: Brown Eyes Genotype: Bb or BB
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I. Background Norm of reaction : the set of phenotypic expressions of a genotype under different environmental conditions Phenotypic plasticity : environmentally induced variation in the phenotype
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Environment Phenotypic character Genotype A ; Genotype B Obligate trait: expression determined by genes ONLY Facultative trait: expression determined by genes and the environment Environment
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Color phases of the snow goose are determined by a single gene. Environment (e.g. temperature) Phenotypic character (goose color)
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Environment (dietary carotenoids) Phenotypic character (Red/orange color) Coloration in male house finches is determined by the amount of carotenoids in the diet.
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Environment (plant diet) Phenotypic character (twig vs. catkin mimic) Larval diet determines the morphology of Nemoria arizonaria (moth): (a) catkin diet - catkin morphology, (b) leaf diet - twig morphology.
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Adaptation : genetic change in a population in response to natural selection Phenotypic plasticity : acclimation : reversible phenotypic change in response to environmental variation (e.g., house finch) developmental response : irreversible phenotypic change in response to environmental cues (e.g., Nemoria arizonaria, moth larvae ) Reversible and irreversible phenotypic changes form a continuum .
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BILD 3 Lecture 3: Natural Selection I. Background II. Artificial selection III. Variation IV. Measuring evolution by natural selection V. Modes of selection
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II. Artificial selection - natural selection imposed by humans for a specific goal , as in the breeding of crops, animals Examples: dogs, pigeons, cruciferous vegetables
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Brussels sprouts broccoli cauliflower kohlrabi kale Wild cabbage or mustard (common ancestor) Artificial selection: Brassica oleracea cabbage
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How did cauliflower come to be? 1. Individuals vary naturally (flower type) 2. Individuals with certain traits selected for breeding and these individuals have greater survival and reproduction as a consequence 3. If variation is heritable (genetic), then (over time) 4. the result is evolution ???
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Lec 3 Bild 3 2011 for Ted(1) - BILD 3 Lecture 3: Natural...

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