Chapter 23

Chapter 23 - 19:12 Chapter23:TheEvolutionofPopulations

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19:12 Chapter 23: The Evolution of Populations The Smallest Unit of Evolution o One common misconception about evolution is that individual organisms  evolve during their lifetime o Evolutionary processes (e.g., natural selection) acts on individuals, but  populations evolve Populations o Figure 23.5 o Population: a localized group of individuals that are capable of  interbreeding and producing fertile offspring that makes evolution possible Mutation o Mutations: changes in nucleotide sequence of DNA Source of new alleles and genes o Point mutation: change in one nucleotide base in a gene o Chromosomal mutations: delete, disrupt, or rearrange many loci on a  chromosome o Gene duplications: duplication of whole segments of a chromosome o Mutation rate averages 1 in every 100,000 genes per generation Sexual Recombination o In sexually reproducing organisms, sexual recombination produces most  of the variability in each generation Variation within a Population o Discrete characters: classified on an either-or basis E.g., flower color in pea plants
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This note was uploaded on 02/22/2010 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Chapter 23 - 19:12 Chapter23:TheEvolutionofPopulations

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