1. End Show 16-2 Evolution as Genetic Change Slide 1 of 40 Copyright Pearson Prentice Hall Genetic Drift What is genetic drift?

2. End Show 16-2 Evolution as Genetic Change Slide 2 of 40 Copyright Pearson Prentice Hall Genetic Drift A random change in allele frequency is called genetic drift.

3. End Show 16-2 Evolution as Genetic Change Slide 3 of 40 Copyright Pearson Prentice Hall Genetic Drift In small populations, individuals that carry a particular allele may leave more descendants than other individuals do, just by chance. Over time, a series of chance occurrences of this type can cause an allele to become common in a population.

4. End Show 16-2 Evolution as Genetic Change Slide 4 of 40 Copyright Pearson Prentice Hall Genetic Drift Genetic drift may occur when a small group of individuals colonizes a new habitat. Individuals may carry alleles in different relative frequencies than did the larger population from which they came. The new population will be genetically different from the parent population.

5. End Show 16-2 Evolution as Genetic Change Slide 5 of 40 Copyright Pearson Prentice Hall Genetic Drift

6. End Show 16-2 Evolution as Genetic Change Slide 6 of 40 Copyright Pearson Prentice Hall Genetic Drift

7. End Show 16-2 Evolution as Genetic Change Slide 7 of 40 Copyright Pearson Prentice Hall Genetic Drift

8. End Show 16-2 Evolution as Genetic Change Slide 8 of 40 Copyright Pearson Prentice Hall Genetic Drift Descendants Population APopulation B

9. End Show 16-2 Evolution as Genetic Change Slide 9 of 40 Copyright Pearson Prentice Hall Genetic Drift When allele frequencies change due to migration of a small subgroup of a population it is known as the founder effect.