Powerpoint going into detail concerning natural selection.

1. Garielle Wagnac Natural Selection

2. So…….what is natural Selection? Who knows?

3. Natural Selection……… It’s a process Beneficial traits inherited become more common in consecutive generations Causes evolution to occur Happens because of adaptation

4. Yes, Natural Selection favors individuals! BUT WHICH?!?!

5. Reproductive Success Likelihood of an individual contributing fertile offspring to the next generation Traits favorable to reproductive success Two categories of traits Characteristics organisms better adapted Traits associated with reproductive success

6. Principles of Natural Selection Allele variation due to mutation (may alter function of protein) Some alleles enhance reproductive success Beneficial alleles more likely to survive Allele frequency change through natural selection

7. How do you measure reproductive success? FITNESS likelihood that a genotype will contribute to gene pool of next generation compared to other genotypes Mean Fitness average reproduction success of members *as mean increases, so does natural selection of organisms

8. AA produces 5 offspring Aa produces 4 offspring aa produces 1 offspring

9. Natural Selection Paths There are 4!

10. Directional Selection Individuals at one extreme of phenotypic range have greater reproductive success in a particular environment Arise from? New allele added Expose to change in environment

11. Stabilizing Selection Favors individuals with intermediate phenotypes an selects against those with extreme phenotypes Tends to decrease genetic diversity

13. Diversifying (Disruptive) Selection Favors the survival of two or more different genotypes that produce different phenotypes Likely to occur in populations that occupy heterogeneous environments

15. Balancing Selection Type of natural selection that maintains genetic diversity Balanced polymorphism occurs 2+ alleles kept in balance of each other Can happen by…….

16. Balancing Selection Heterozygote Advantage Phenomenon where heterozygotes have a higher fitness than the corresponding homozygotes Negative frequency-dependent selection Fitness of a genotype decreases when its frequency becomes higher!

19. NOW YOU KNOW EVERYTHING ABOUT NATURAL SELECTION! At least, I hope so!