Lamarck

1. Lamarck = Inheritance of acquired characteristics Giraffe stretches neck over several generations to reach leaves high in trees Lamarck

2. Natural selection – favorable new traits resulting from random mutations are passed on to succeeding generations Darwin

3. Darwin = Proposes the “Origin of Species” (by natural selection) 5 year world cruise

5. Ancestral bird “adapts” (by natural selection) into various habitats seeds leaves fruit Vegetarian insects insects Ancestor? grubs Uses tools seeds cactus Woodpecker Darwin’s Finches

7. Microevolution: Change in the gene frequency within a population Provides new genetic material for new traits …… without which all life would look the same ….. like the first life.

8. Many bacteria, including resistant variety Expose all bacteria to antibiotics; most normal die Resistant bacteria multiply and dominate Entire infection evolves into resistant strain

9. Add Antibiotic % RESISTANCE Normal bacteria Resistant bacteria Dead bacteria Example of microevolution

10. Causes of microevolution: • Mutation – nucleotide or chromosome • Non random mating – mate selection • Gene Flow - migration • Genetic Drift – accidental loss of individuals • Natural Selection – most fit reproduce more often

11. UV light Thymine dimer

12. Radiation (x-ray) causes chromosome damage

13. With and without mutation No mutation mutation No mutation No mutation No mutation mutation

14. Factors that will cause microevolution: • Mutation – nucleotide or chromosome change • Non random mating – mate selection • Gene Flow - migration • Genetic Drift – accidental loss of individuals • Natural Selection – most fit reproduce more often

15. Non random mating The wolf is probably close to natural dog if dogs allowed to mate freely Specific breeds of dog result if dogs are only allowed to breed with others in the same breed

16. 20,000 Cheetahs • Extreme example of nonrandom mating = inbreeding • Results in mostly homozygous genotypes (e.g. HH or hh) • Cubs low survival rate • Susceptible to disease • Males have low sperm count • Only chance for new genes is through mutation

17. Factors that will cause microevolution: • Mutation – nucleotide or chromosome change • Non random mating – mate selection • Gene Flow - migration • Genetic Drift – accidental loss of individuals • Natural Selection – most fit reproduce more often

18. Gene flow (migration) Genes for the brown beetle move to green population Population A = 100% green Population B = 100% brown

19. Factors that will cause microevolution: • Mutation – nucleotide or chromosome change • Non random mating – mate selection • Gene Flow - migration • Genetic Drift – accidental loss of individuals • Natural Selection – most fit reproduce more often

20. Genetic Drift: accidental loss of members of a small population 33% purple 20% purple 33% purple 32% purple

21. Small population with 12.5% white and 87.5% dark 75% dark 25% white 100% dark 0% white

22. Factors that will cause microevolution: • Mutation – nucleotide or chromosome change • Non random mating – mate selection • Gene Flow - migration • Genetic Drift – accidental loss of individuals • Natural Selection – most fit reproduce more often

23. Light moth reproduces more often – why? Dark moth reproduces more often – why? Bird eats dark moth Bird eats light moth Best adapted moth reproduces more offspring

24. Natural Selection does not give an organism an adaptation simply because it will do better with it. – Adaptations occur by chance mutations

25. Factors that will cause microevolution: • Mutation – nucleotide or chromosome change • Non random mating – mate selection • Gene Flow - migration • Genetic Drift – accidental loss of individuals • Natural Selection – most fit reproduce more often Review

26. SPECIES = group of interbreeding populations reproductively isolated from other populations Are lions and tigers separate species? Liger = lion x tiger

27. Are horse and donkey different species?? Horse X Donkey = Mule (sterile) No meiosis sperm egg

28. Ensatina eschscholtzii

29. Geographic Isolation can lead to differences and new species Ensatina eschscholtzii Becomes separate species as mutations make them different

30. Kaibab and Abert’s squirrels separated by Grand Canyon = geographic isolation Colorado River

31. Geographic isolating mechanisms (fences) prevent exchange of genetic differences between dog breeds allowing differences to build-up

32. If population is geographically isolated long enough, then behavioral isolating mechanisms occur