Mom, Dad… There’s something you need to know… I’m a MAMMAL!

1. Mom, Dad… There’s something you need to know… I’m a MAMMAL! Origin of Species Chpt. 24

2. “That mystery of mysteries…” Darwin never actually tackled how new species arose… Both in space and time, we seem to be brought somewhat near to that great fact—thatmystery ofmysteries—the first appearance of new beings on this Earth.

3. origin of new taxonomic groups Macroevolution macroevoluti macroevolu macroevo

4. origin of new species speciation speciati specia spec

5. HOW?? speciation - origin of a new speciesKEYTO MACROEVOLUTION!!

6. Anagenesis= one species transforming into oneother species Nobiologicaldiversity created speciation= origin of a new species

7. Cladogenesis= one species transforming into more species Biological diversity created speciation=origin of a new species

8. SPECIES

9. SPECIES potential to interbreed produce viable offspring

10. So…what is a species? • Biological species concept • defined by Ernst Mayr • population whose members can interbreed & produce viable, fertile offspring • reproductively compatible Distinct species:songs & behaviors are different enough to prevent interbreeding Eastern Meadowlark Western Meadowlark

11. Question How many species of African Violets are here? SPECIES

12. What factors/ barriers can isolate gene pools? mixing

13. What factors isolate gene pools?

14. Prezygotic Barriers

15. What factors isolate gene pools?

16. What factors isolate gene pools? Habitat Isolation

17. allopatric • geographic separation

18. What factors isolate gene pools? Temporal Isolation

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

20. What factors isolate gene pools? Blue footed boobies mate only after a courtship display unique to their species Behavioral Isolation • reproductive isolation

21. What factors isolate gene pools? Behavioral Isolation • reproductive isolation

22. What factors isolate gene pools? sympatric speciation? 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. Mechanical Isolation Plants

23. What factors isolate gene pools? sympatric speciation? Animals • For 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! Mechanical Isolation

24. What factors isolate gene pools? sympatric speciation Gametic Isolation

25. Gametic isolation • Sperm of one species may not be able to fertilize eggs of another species • mechanisms • biochemical barrier so sperm cannot penetrate egg • receptor recognition: lock & key between egg & sperm • chemical 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.

26. PostZygotic Barriers

27. What factors isolate gene pools? Reduced Hybrid Viability

28. What factors isolate gene pools? Reduced Hybrid Fertility ex. mules

29. Reduced hybrid fertility • Even 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 Mules are vigorous, but sterile Horses have 64 chromosomes (32 pairs) Donkeys have 62 chromosomes (31 pairs) Mules have 63 chromosomes!

30. What factors isolate gene pools? Hybrid breakdown F1 fine, subsequent… no good

31. Hybrid breakdown sympatric speciation? • Hybrids 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.

33. How does Speciation Occur?

34. =AllopatricSpeciation ex. Adaptive radiation

35. ex. Adaptive radiation

36. ex. Adaptive radiation

37. ex. Adaptive radiation

38. ex. Adaptive radiation

39. ex. Adaptive radiation

40. ex. Adaptive radiation

41. Polyploidy 2N 4N =SympatricSpeciation TEMPO of evolution

42. BIG changes occur b/c of the accumulation of small changes • Polyploidy 2N 4N =SympatricSpeciation GRADUALISM

43. Polyploidy 2N 4N =SympatricSpeciation TEMPO of evolution

44. Polyploidy 2N 4N =SympatricSpeciation Big changes as it “buds” from parent species, few changes after that Stephen J. Gould – 1972

46. change in rate & timing of developmental events in various parts of the body how did we differentiate ????????

47. change in rate & timing of developmental events in various parts of the body how did we differentiate???????? If these genes are altered, the timing of development and rate will be altered within the species

48. change in rate & timing of developmental events in various parts of the body how did we differentiate???????? If these genes are altered, the timing of development and rate will be altered within the species

49. Hox Genes 1983 -Dr. Thomas Kaufman - Indiana University discovered Clusters of genes, involved in the regulation of development of animals, plants, fungi

50. Hox Genes Evolved in the paleozoic era