1. Evolution of Populations

2. Darwin and Mendel Genes control heritable traits Changes in genes = variation Natural selection works with this variation

3. Different alleles Dominant, recessive, multiple alleles, etc. Heterozygous genotypes Can pass on dominant OR recessive

4. Combined genetic info. of all members of a population Relative frequency: # of times an allele appears in a gene pool compared to other alleles Has nothing to do with dominant/recessive Evolution = change in relative frequency of alleles in a population

5. What is the biggest source? 1. mutations! 2. gene shuffling- ½ from mom and ½ from dad Random gamete formation

6. Single-gene trait: controlled by one gene with 2 alleles Ex: widow’s peak (2 possible phenotypes) Polygenic trait: controlled by 2 or more genes Ex: skin color (many possible phenotypes)

7. Evolutionary fitness- organisms success in passing genes on to offspring Evolutionary adaptations increase ability to pass on a trait Survive = pass genes on Fail = do NOT pass genes on Evolution acts on organisms NOT single genes! Populations evolve NOT organisms

8. Natural selection affects the distribution of phenotypes (bell curve) 3 Types: 1. directional selection: when individuals at one end of the curve have increased fitness

9. 2. stabilizing selection: when individuals at the center of the curve have increased fitness

10. 3. disruptive selection: when individuals at both ends of the curve have increased fitness *may eventually split into 2 different species

11. Genetic drift: random change in allele frequency that occurs in a small population By chance certain alleles are passed on over others Founder effect: change in allele frequency due to the migration of a small subgroup of a population

12. Hardy-Weinberg Principle: allele frequency in a population will remain constant as long as the following factors take place: 1. random mating 2. large population 3. no movement in/out of a population 4. no mutations 5. no natural selection So, does this ever happen? No, not really

13. Species: group of organisms that breed together and produce offspring Share a gene pool Speciation: formation of new species All different species!

14. A separation of gene pools Reproductive isolation: separation so that two organisms cannot breed No offspring are produced

15. behavioral: different mating behaviors Ex: meadowlark’s song geographic*: physical barrier separating Ex: Abert and Kaibob squirrels temporal: reproduce at different times Ex: orchid pollen release

16. Peter and Rosemary Grant- Princeton Tested Darwin’s hypothesis with finches Needed to prove 2 things: 1. natural genetic variations were present 2. variations caused a difference in fitness Success- more support for Darwin! Go Darwin!

17. All species of finch came from 1 founding population: 1. founders arrive from mainland 2. geographic isolation (separates gene pools) 3. changes to new gene pools- adapt to local environment 4. reproductive isolation- 2 new species can no longer mate 5. ecological competition- 2 species live together, become more different to increase survival