1. Mechanisms of Evolution & their Effects on Populations

2. NEW VOCABULARY POPULATION – GROUP OF INDIVIDUALS OF SAME SPECIES THAT INTERBREED POPULATION – GROUP OF INDIVIDUALS OF SAME SPECIES THAT INTERBREED GENE POOL – COMMON GROUP OF ALL GENES PRESENT IN A POPULATION GENE POOL – COMMON GROUP OF ALL GENES PRESENT IN A POPULATION

3. Gene Pool Combined genetic info. of all members Allele frequency is # of times alleles occur

4. A. Variation in Populations 2 processes can lead to this: Mutations - change in DNA sequence Gene Shuffling – from sexual reproduction

5. B. Genetic Drift changes populations = random change in allele frequency causes an allele to become common

6. B. Genetic Drift- Founder Effect: a cause of genetic drift attributable to colonization by a limited number of individuals from a parent population B. Genetic Drift- Founder Effect: a cause of genetic drift attributable to colonization by a limited number of individuals from a parent population

7. B. Genetic Drift- Bottleneck Effect: = changes in gene distribution that result from a rapid decrease in population size.

8. C. Gene Flow (migration): genetic exchange due to the migration of fertile individuals or gametes between populations (reduces differences between populations) C. Gene Flow (migration): genetic exchange due to the migration of fertile individuals or gametes between populations (reduces differences between populations)

9. D. Nonrandom mating: inbreeding and assortative mating (both shift frequencies of different genotypes)

10. E. Natural Selection: differential success in reproduction; only form of microevolution that adapts a population to its environment

11. F. Sexual selection Sexual dimorphism: secondary sex characteristic distinction Sexual dimorphism: secondary sex characteristic distinction Sexual selection: selection towards secondary sex characteristics that leads to sexual dimorphism Sexual selection: selection towards secondary sex characteristics that leads to sexual dimorphism

12. Evolution of Populations Occurs when there is a change in relative frequency of alleles

13. Phenotype Expression Depends on how many genes control that trait Depends on how many genes control that trait

14. Single-Gene vs. Polygenic Traits Single-Gene: 2 Distinct Phenotypes Polygenic: Many Phenotypes (EG: tongue rolling)

15. Natural Selection- see handout Shifts to Shifts to middle range Shifts to Shifts to 2 extremes Shifts to Shifts to 1 extreme

16. Today: On page 359 of your text, answer #1-11. Use this note & text pages 350-358 to help formulate your answers.