2. Dispatch—Explain this cladogram

3. Practice Evolution Quiz http://tinyurl.com/3nmb6gm

5. Problem 3 If you observe a population and find that 16% show the recessive trait, you know the frequency of the aa genotype. This means you know q2. What is q for this population?

6. Evolution of populations Evolution = change in allele frequencies in a population –hypothetical: what conditions would cause allele frequencies to not change? –non-evolving population REMOVE all agents of evolutionary change 1.very large population size (no genetic drift) 2.no migration (no gene flow in or out) 3.no mutation (no genetic change) 4.random mating (no sexual selection) 5.no natural selection (everyone is equally fit)

7. 5 Agents of evolutionary change Mutation Gene Flow Genetic Drift Selection Non-random mating

8. Application of H-W principle Sickle cell anemia –inherit a mutation in gene coding for hemoglobin oxygen-carrying blood protein recessive allele = H s H s –normal allele = H b –low oxygen levels causes RBC to sickle breakdown of RBC clogging small blood vessels damage to organs –often lethal

9. Sickle cell frequency High frequency of heterozygotes –1 in 5 in Central Africans = H b H s –unusual for allele with severe detrimental effects in homozygotes 1 in 100 = H s H s usually die before reproductive age Why is the H s allele maintained at such high levels in African populations? Suggests some selective advantage of being heterozygous…

10. Malaria Single-celled eukaryote parasite (Plasmodium) spends part of its life cycle in red blood cells 1 2 3

11. Heterozygote Advantage In tropical Africa, where malaria is common: –homozygous dominant (normal) die or reduced reproduction from malaria: H b H b –homozygous recessive die or reduced reproduction from sickle cell anemia: H s H s –heterozygote carriers are relatively free of both: H b H s survive & reproduce more, more common in population Hypothesis: In malaria-infected cells, the O 2 level is lowered enough to cause sickling which kills the cell & destroys the parasite. Hypothesis: In malaria-infected cells, the O 2 level is lowered enough to cause sickling which kills the cell & destroys the parasite. Frequency of sickle cell allele & distribution of malaria

12. Hardy-Weinberg lab pod cast http://www.youtube.com/watch?v=KmqgZv Uoq3k

13. Lab—Part A TasterNonTaster PTC Control Non-Tasters=Homo recessive (aa) Tasters=Homo Dominant (AA) or Heter (Aa) Figure out the p2 and 2pq for our class

14. Results and Discussion 5 Hardy Weinberg calculations Show work—organzied part A-E Discussion: In part A evolution did/did not happen because…. In part B…. In part C Explain WHY, use terms

15. Part B—Testing an ideal Population Initial Class Frequencies GG____ Gg____ gg___ My initial genotype ___ F1____ F2_____ F3_____ F4_____ F5______ Final Class Frequencies GG____ Gg____ gg ___

16. Part C—Selection (homo recessive selected against) Initial Class Frequencies GG____ Gg____ gg___ My initial genotype ___ F1____ F2_____ F3_____ F4_____ F5______ Final Class Frequencies GG____ Gg____ gg___

17. Part D—Heterozygous Advantage (Homo dom—may die of maleria (flip coin; homo recessive—die of sickle cell) Initial Class Frequencies GG____ Gg 24/48 gg___ My initial genotype ___ F1____ F2_____ F3_____ F4_____ F5______ Final Class Frequencies GG 16/48 Gg 32/48 gg 0/48

18. Part E—Genetic Drift (break into 3 smaller populations—make hypothesis) Initial Class Frequencies GG____ Gg____ gg___ My initial genotype ___ F1____ F2_____ F3_____ F4_____ F5______ Final Class Frequencies Frequencies GG____ Gg____ gg___

20. Macroevolution: the origin of new taxonomic groups Speciation: the origin of new speciesSpeciation: the origin of new species 1- Anagenesis (phyletic evolution): accumulation of heritable changes1- Anagenesis (phyletic evolution): accumulation of heritable changes 2- Cladogenesis (branching evolution): budding of new species from a parent species that continues to exist (basis of biological diversity)

21. What is a species? Biological species concept (ErnstMayr): a population or group of populations whose members have the potential to interbreed and produce viable, fertile offspring (genetic exchange is possible and that is genetically isolated from other populations)Biological species concept (ErnstMayr): a population or group of populations whose members have the potential to interbreed and produce viable, fertile offspring (genetic exchange is possible and that is genetically isolated from other populations)

22. How and why do new species originate? Species are created by a series of evolutionary processesSpecies are created by a series of evolutionary processes –populations become isolated geographically isolatedgeographically isolated reproductively isolatedreproductively isolated –isolated populations evolve independently

23. Dispatch—Draw and explain Modes of speciation (based on how gene flow is interrupted) Allopatric: “other country” populations segregated by a geographical barrier; can result in adaptive radiation (island species)Allopatric: “other country” populations segregated by a geographical barrier; can result in adaptive radiation (island species) Sympatric: “same country reproductively isolated subpopulation in the midst of its parent population (change in genome); polyploidy in plants; cichlid fishesSympatric: “same country reproductively isolated subpopulation in the midst of its parent population (change in genome); polyploidy in plants; cichlid fishes

24. Reproductive Isolation (isolation of gene pools), I Prezygotic barriers: impede mating between species or hinder the fertilization of the ovaPrezygotic barriers: impede mating between species or hinder the fertilization of the ova Habitat (snakes; water/terrestrial)Habitat (snakes; water/terrestrial) Behavioral (fireflies; mate signaling)Behavioral (fireflies; mate signaling) Temporal (salmon; seasonal mating)Temporal (salmon; seasonal mating) Mechanical (flowers; pollination anatomy)Mechanical (flowers; pollination anatomy) Gametic (frogs; egg coat receptors)Gametic (frogs; egg coat receptors)

25. Habitat isolation Species occur in same region, but occupy different habitats so rarely encounter each otherSpecies occur in same region, but occupy different habitats so rarely encounter each other –reproductively isolated 2 species of garter snake, Thamnophis, occur in same area, but one lives in water & other is terrestrial lions & tigers could hybridize, but they live in different habitats:  lions in grasslands  tigers in rainforest lions & tigers could hybridize, but they live in different habitats:  lions in grasslands  tigers in rainforest

26. Temporal isolation Species that breed during different times of day, different seasons, or different years cannot mix gametesSpecies that breed during different times of day, different seasons, or different years cannot mix gametes –reproductive isolation Eastern spotted skunk (L) & western spotted skunk (R) overlap in range but eastern mates in late winter & western mates in late summer

27. Behavioral isolation Unique behavioral patterns & rituals isolate speciesUnique behavioral patterns & rituals isolate species –identifies members of species –attract mates of same species –attract mates of same species courtship rituals, mating callscourtship rituals, mating calls reproductive isolationreproductive isolation Blue footed boobies mate only after a courtship display unique to their species

28. Mechanical isolation Morphological differences can prevent successful matingMorphological differences can prevent successful mating –reproductive isolation Even in closely related species of plants, the flowers often have distinct appearances that attract different pollinators. These 2 species of monkey flower differ greatly in shape & color, therefore cross- pollination does not happen. Plants sympatric speciation?

29. Mechanical isolation For many insects, male & female sex organs of closely related species do not fit together, preventing sperm transferFor many insects, male & female sex organs of closely related species do not fit together, preventing sperm transfer –lack of “fit” between sexual organs: hard to imagine for us… but a big issue for insects with different shaped genitals! Damsel fly penises Animals

30. Gametic isolation Sperm of one species may not be able to fertilize eggs of another speciesSperm of one species may not be able to fertilize eggs of another species –mechanisms biochemical barrier so sperm cannot penetrate eggbiochemical barrier so sperm cannot penetrate egg –receptor recognition: lock & key between egg & sperm chemical incompatibilitychemical incompatibility –sperm cannot survive in female reproductive tract Sea urchins release sperm & eggs into surrounding waters where they fuse & form zygotes. Gametes of different species— red & purple —are unable to fuse.

31. Gametic isolation Sperm of one species may not be able to fertilize eggs of another speciesSperm of one species may not be able to fertilize eggs of another species –mechanisms biochemical barrier so sperm cannot penetrate eggbiochemical barrier so sperm cannot penetrate egg –receptor recognition: lock & key between egg & sperm chemical incompatibilitychemical incompatibility –sperm cannot survive in female reproductive tract Sea urchins release sperm & eggs into surrounding waters where they fuse & form zygotes. Gametes of different species— red & purple —are unable to fuse.

32. Reproductive Isolation, II Postzygotic barriers: fertilization occurs, but the hybrid zygote does not develop into a viable, fertile adultPostzygotic barriers: fertilization occurs, but the hybrid zygote does not develop into a viable, fertile adult Reduced hybrid viability (frogs; zygotes fail to develop or reach sexual maturity)Reduced hybrid viability (frogs; zygotes fail to develop or reach sexual maturity) Reduced hybrid fertility (mule; horse x donkey; cannot backbreed)Reduced hybrid fertility (mule; horse x donkey; cannot backbreed) Hybrid breakdown (cotton; 2nd generation hybrids are sterile)Hybrid breakdown (cotton; 2nd generation hybrids are sterile)

34. Reduced hybrid viability Genes of different parent species may interact & impair the hybrid’s developmentGenes of different parent species may interact & impair the hybrid’s development Species of salamander genus, Ensatina, may interbreed, but most hybrids do not complete development & those that do are frail.

35. Mules are vigorous, but sterile Reduced hybrid fertility Even if hybrids are vigorous they may be sterileEven if hybrids are vigorous they may be sterile –chromosomes of parents may differ in number or structure & meiosis in hybrids may fail to produce normal gametes Donkeys have 62 chromosomes (31 pairs) Horses have 64 chromosomes (32 pairs) Mules have 63 chromosomes!

36. Hybrid breakdown Hybrids may be fertile & viable in first generation, but when they mate offspring are feeble or sterileHybrids may be fertile & viable in first generation, but when they mate offspring are feeble or sterile In strains of cultivated rice, hybrids are vigorous but plants in next generation are small & sterile. On path to separate species. In strains of cultivated rice, hybrids are vigorous but plants in next generation are small & sterile. On path to separate species.