presentation_13 - 1 Lecture 13 Evolution by natural...

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Unformatted text preview: 1 Lecture 13 Evolution by natural selection What is it? What happens without it? Goals of Micro-evolutionary Biology Understanding processes of evolutionary change in populations. How processes account for the amount and distribution of genetic variation within and among populations. How does divergence among populations contribute to origin of diversity at higher taxonomic levels. 2 Only one of several evolutionary processes resulting in changing allele frequencies over time. Conditions that must be met for evolution by natural selection to take place. Natural Selection Individuals in a population vary in survival, mating ability, and/or fertility, such that some individuals leave more offspring than others. Individuals vary for some character(s). Variation in offspring production is related to variation in the character states (phenotypes). Phenotypes are at least partially heritable - such that more successful variants pass on more copies of their alleles than less successful variants. The frequency of these successful variants increases in the next generation. 3 Natural Selection on Flower Size in the Alpine Skypilot by Bumblebee Pollinators Picture by: Bob Skowron June 1998 Central Colorado Mts Alpine Skypilot Polemonium viscosum Research by Candace Galen 4 Pattern Flowers of alpine skypilot vary in size....
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This note was uploaded on 09/28/2008 for the course BIOEE 2780 taught by Professor Geber during the Fall '07 term at Cornell University (Engineering School).

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presentation_13 - 1 Lecture 13 Evolution by natural...

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