1. The document discusses key concepts of evolution including natural selection, Darwin's theory, adaptations, fitness, artificial selection, and evidence that supports evolution such as homologous structures, fossils, and DNA similarities. 2. It also covers speciation, reproductive isolation through behavioral, geographic and temporal means, and forms of natural selection like sexual selection. 3. Finally, it defines convergent and divergent evolution, with convergent evolution creating analogous structures and divergent evolution creating homologous structures through genetic drift.

1. Chapter 15 Notes

3. Key Terms Evolution : Changes in a population over time. Natural Selection : The environment favors individuals to survive and reproduce successfully “AKA, Survival of the Fittest” Individuals do not evolve, populations do .

4. Darwin’s Theory: The Short Version 1. Organisms differ; variation is inherited 2. Organisms produce more offspring than survive 3. Organisms compete for resources 4. Organisms with advantages survive to pass those advantages to their children 5. Species alive today are descended with modifications from common ancestors

5. Example: Colored Moths The traits that help an organism survive in a particular environment are “selected” in natural selection

9. Key Terms Adaptation : An inherited characteristic that increases an organism’s ability to survive and reproduce in its specific environment. Fitness : The ability to survive and reproduce in a specific environment. Adaptations make an organism more fit.

10. Key Terms Artificial Selection : Nature provides the variation and human select those variances they find useful. Example: a farmer breeds only his best livestock.

11. Evidence for Evolution 1. The Fossil Record 2. Homologous Body Structures 3. Similarities in Embroyology 4. Vestigial Structures 5. Similarities in DNA and RNA

12. Homologous Structures Same structures-Different function Example: Human arm, bird wing

13. Homologous Structures

14. Embryology

15. Analogous Structures Different structure, Same function Example: Butterfly wing, bird wing

16. Vestigial Structures Body structures that no longer have a use Example: Human appendix

17. Gene Pool Gene Pool : The combined collection of alleles for all traits in a population.

18. Three Forms of Natural Selection

19. Sexual Selection Sexual Selection : A special case of selection that occurs when the choice of mates is based on a trait (or traits). Sexual selection may be directional, stabilizing, or disruptive.

20. Sexual Selection

21. Evolving New Species Speciation : The evolution of a new species. In order for speciation to occur, populations (or segments of populations) must become reproductively isolated. There are 3 ways that a population can become reproductively isolated.

22. Reproductive Isolation Behavioral Isolation ; Occurs when two populations are physically capable of interbreeding, but have different reproductive behaviors. Geographic Isolation : Occurs when a physical barrier (mountain, lake, etc.) separates two populations. Temporal Isolation : Occurs when populations are capable of interbreeding, but each breed at different times.

23. Behavioral Isolation Courtship rituals, like these, are critical for mating within a species, but ineffective for attracting members of other species.

24. Geographic Isolation

25. Geographic Isolation

26. Temporal Isolation

27. Convergent and Divergent Evolution Convergent Evolution : Two unrelated species develop similar traits due to similar environments. Convergent evolution causes Analogy . Divergent Evolution : Two similar species develop differences due to different environments. Divergent Evolution causes Homology .

28. Genetic Drift Change in the frequency of alleles due to natural disasters. Example: tornado, hurricane, flood…