BIO Chapter 23

BIO Chapter 23 - Chapter 23 Wednesday, January 21, 2009...

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Chapter 23 Wednesday, January 21, 2009 1:38 PM THE EVOLUTION OF POPULATIONS 1. The smallest unit of evolution o One common misconception about evolution is that individual organisms evolve during their life time o Evolutionary processes (e.g. natural selection) acts on individual, but populations evolve 2. Concept 23.1 : mutation and sexual recombination produce the genetic variation that make evolution possible 3. Variation within a population o Discrete characters: classified on an either-or basis Ex: flower color in pea plants o Quantitative character: vary along a continuum within a population Ex: height, weight 4. 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 mutation 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 5. Sexual reproduction o In sexually reproducing organisms, sexual recombination produces most of the variability in each generation. 6.
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This note was uploaded on 01/29/2009 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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BIO Chapter 23 - Chapter 23 Wednesday, January 21, 2009...

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