chapter 23

chapter 23 - Chapter 23 THE EVOLUTION OF POPULATIONS The...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 23 THE EVOLUTION OF POPULATIONS The smallest unit of evolution One common misconception about evolution is that individual organisms evolve during their lifetime Evolutionary processes ( e.g., natural selection ) acts on individuals but populations evolve Mutation and sexual recombination produce genetic variation that makes evolution possible Variation within a population Discrete characters: classified on an either or basis - E.g flower color in pea plants Quantitative characters: vary along a continuum within a population - E.g., height, weight Mutation Change in nucleotide sequence of DNA - Source of new alleles and genes Point mutation: change in one nucleotide base in a gene Chromosomal mutations: delete, disrupt, or rearrange many loci on a chromosome Gene duplications: duplication of whole segments of a chromosome Mutation rate averages 1 in every 100,000 genes per generations Due to transposable elements, they are able to insert themselves into a sequence and disrupt it Sexual Recombination In sexually reproducing organisms, sexual recombination produces most of the variability in each generation. What provides selective pressure in artificial selection? -
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/15/2010 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

Page1 / 2

chapter 23 - Chapter 23 THE EVOLUTION OF POPULATIONS The...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online