Lesson 4 Agenda

1. Lesson 4 Agenda Mechanisms of Evolution NO ISLAND BIOGEOGRAPHY – next Monday Continue discussion of mechanisms for selection PowerPoint Slide Show with questions throughout Ms. Baker’s Recommendation: Take notes! Copies of the slides are available online Organization Time This time is dedicated to: 1) Grade checks with Ms. Henshaw 2) Organizing Week 2 3) Asking questions Week 2 Due Date Week 2 Packet will be due at the beginning of class on: MONDAY, May 6th, 2013 Feel free to turn it in today if you don’t want to worry about it over the weekend!

2. Genghis Khan • According to historical researchers, Genghis Khan was responsible for the death of over 40,000,000 during his 20 year reign. • Some modern scientists say it is possible that Genghis Khan has between 16,000,000 and 25,000,000 living descendants. • Do you think Genghis Khan was a fit individual? • Why or why not? • Have any other humans in history • been as successful as Genghis Khan • in terms of genetic fitness?

3. RadioLabMaking of the Fittest

4. Genghis Khan • According to historical researchers, Genghis Khan was responsible for the death of over 40,000,000 during his 20 year reign. • Some modern scientists say it is possible that Genghis Khan has between 16,000,000 and 25,000,000 living descendants. • Do you think Genghis Khan was a fit individual? • Why or why not? • Have any other humans in history • been as successful as Genghis Khan • in terms of genetic fitness?

5. 5 Mechanisms of Evolution • Random Mutation • Gene Flow (aka Migration) • ? (Hint: this is were we ended last class…) • ? • ?

6. Remember back to last class…3. Genetic Drift Reduction of Genetic Variation Random Death Small Beginning Population

7. 3. Genetic Drift Bottleneck Event Founder Effect Different events, similar results: reduced genetic variation

8. Bottleneck Events

9. Founder Effect

10. Comparing Types of Genetic Drift Random bad luck Dramatically reduced Reduced genetic variation Reduced genetic variation Migration Still present, but far away

11. Remember back to last class…3. Genetic Drift BottleneckEvent Founder Effect A founder effect occurs when a new colony is started by a few members of the original population.  Population bottlenecks occur when a population’s size is dramatically reduced for at least one generation Different events, similar results: reduced genetic variation

12. Genghis Khan’s Conquests • Is this an example of genetic drift? If you think it is, was this an example of a bottleneck or of the founder effect? If not, what evidence do you have to say that this is not genetic drift?

13. 5 Mechanisms of Evolution • Random Mutation • Gene Flow (aka Migration) • Genetic Drift • ? • ?

14. 4. Non-Random Mating Non-random mating occurs when there is a bias for or against mating with certain individuals. For example: Sexual Selection http://www.pbs.org/wgbh/evolution/library/01/6/l_016_09.html

15. 5 Mechanisms of Evolution • Random Mutation • Gene Flow (aka Migration) • Genetic Drift • Non-Random Mating • ? (Hint: It’s the *primary* mechanism for evolution!)

16. Hold on now… • What was that learning target again??? I can explain how natural selection works as the primary mechanism for evolution.

17. Genetic variation • Struggle for existence • Differential survival & reproduction • Production of offspring Evolution via Natural Selection http://www.dnatube.com/video/11928/Natural-Selection-and-Adaptation

18. Think Pair Share Your friend says to you, “Malaria caused sickle cell to show up in humans”… What would you say to your friend to help them better understand this relationship?

19. 5. Natural Selection Natural selection works because some phenotypes are more successful than others in a given environment. Successful (adaptive) genotypes become more common in later generations, causing a change in gene frequency over time… that leads to increase in fitness!

20. 5. Natural Selection Natural selection leads to adaptation – an increase in the frequency of fit genes of a population in a particular environment.

21. Think Pair Share Is domestication and the selective breeding of crops and livestock a form of natural selection?

22. Three Forms of Natural Selection

23. Human Birth Weight Is Under Stabilizing Selection • What effect can modern medicine have on selection?

24. Directional Selection in cacti population • Does the cacti “choose” to have more thorns?

25. Disruptive Selection in the Grand Canyon Kaibab squirrel (Sciurus aberti kaibabensis, left) and Abert squirrel (Sciurus aberti aberti, right) became geographically isolated about 10,000 years ago.

26. Think Pair Share How can pure chance (mutation) create new complex structures or processes, much less new species?

27. Think Pair Share Does the theory of natural selection suggest an optimistic or a pessimistic view of the world?

28. Think Pair Share Mutations happen randomly, without regard to how they effect, an organism. That said, does having the sickle cell mutation benefit or harm a human organism? What effect can an individual having a mutation that is beneficial in a certain environment have on the population?

29. Think Pair Share Why do we still have wisdom teeth if dentists just pull them out?

30. Next Week • Island Biogeography Lab The Canary Islands http://www.youtube.com/watch?v=SC4ctwvbo1w http://www.youtube.com/watch?v=aLMV_vUfcvs