Biology 2483A Lecture 5: evolution and ecology

• School: Western University
• Department: Biology
• Course: Biology 2483A
• Professor: Hugh Henry

Document Summary

Mutation: different alleles arise by mutation: random errors/changes in dna, mutations can result from copying errors during cell division, mechanical damage, exposure to chemicals (mutagens) or high-energy radiation. Formation of new alleles is critical to evolution: allows for variation. If mutation did not produce new alleles, all members of a population would have identical genotypes and evolution could not occur. In a generation, one mutation would occur in every 10,000 to 1,000,000 copies of a gene. In one generation, mutation acting alone causes virtually no change in allele frequencies of a population. Short time scale of generations do not see changes in allele frequencies. Mechanisms of evolution: natural selection, genetic drift, and gene flow can cause allele frequencies in a population to change over time. Individuals with certain heritable traits survive and reproduce more successfully than other individuals: not only are you looking for traits for individuals to survive, but it has to be heritable traits.