2. Have out your Microevolution HW. If you did not complete it: leave your group and go complete it. You can go through what you miss on your own after I post this power point. If you did your HW good job! I would like you to review your answers. Pay particular attention to #5 and the scenarios/graphs you came up with. This should take 10 minutes or less. Watch your time!

3. Types of Natural Selection A.) Most traits are polygenic: controlled by many genes. 1.) These traits therefore have a normal distribution and a characteristic shape when phenotypes are graphed.

4. Ex: Height in Humans

5. B.) Natural Selection can change this normal distribution in 3 ways. Your challenge was to figure this out. I know it was probably pretty difficult but thinking is good for you! 1.) Directional Selection: individuals at one end of the curve have higher fitness than individuals at the middle or other end.

6. Directional Selection Food becomes scarce. Key Low mortality, high fitness High mortality, low fitness Ex: Beak Size of finches So, The population curve shifts towards one extreme of the curve. This is pretty common.

7. 2.) Stabilizing Selection: individuals at the center of the curve have higher fitness. So, The population curve favors the middle of the curve and you lose the extremes.

8. Key Percentage of Population Birth Weight Selection against both extremes keep curve narrow and in same place. Ex: Normal weight human babies vs. high or low birth weight. Low mortality, high fitness High mortality, low fitness Stabilizing Selection Human baby birth weight is the classic example. Babies that are small don’t survive as well and babies that are too big can’t get out (until C- section was developed … we could be selecting for bigger babies!)

9. 3.) Disruptive Selection: individuals at both ends of the curve have higher fitness than individuals in the middle.

10. Disruptive Selection Largest and smallest seeds become more common. Number of Birds in Population Beak Size Population splits into two subgroups specializing in different seeds. Beak Size Ex: Food goes from medium size seeds to large and small seeds. Birds with small & large beaks are now favored. Number of Birds in Population Key Low mortality, high fitness High mortality, low fitness So, The population curve increases towards two extremes. This is not as common. You should watch the Crash Course at home that I have posted at the end they have an example of a daphnia that seems to be in disruptive selection.

11. http://wps.prenhall.com/wps/media/objects/ 1110/1136802/17_3.html this is pretty slow but it does review the 3 types of selection. Watch it now. http://wps.prenhall.com/wps/media/objects/ 1110/1136802/17_3.html Crash course discusses it too but that’s you tube so you’ll have to do that at home. http://www.youtube.com/watch?v=aTftyFboC _M 8:18-12:33 c.c. types of selection http://www.youtube.com/watch?v=aTftyFboC _M

12. Optional Review at home: http://www.youtube.com/watch?v=WhFKPaR nTdQ effects on allele frequency. This is also crash course. You may like a review of microevolution. Stop around 6:40 when he starts using the H-W equation. http://www.youtube.com/watch?v=WhFKPaR nTdQ

13. In broader terms, these changes from generation to generation can result in speciation: the formation of new species. a. This can be thought of as descent with modification. b. Through change from generation to generation, one species may separate into two. c. This idea implies that ALL life originated from a common ancestor with speciation occurring over and over again!

14. Remember: Two Ways to Look At Evolution Microevolution Changes in a gene pool of a population E.g. a population accumulating longer neck genes, darker fur genes Macroevolution The formation of new species or taxonomic groups How did animals evolve, how did mammals evolve etc. We just finished this Moving on to this!

15. Macroevolution Big Changes

16. Macroevolution Is concerned with how new taxonomic groups or species came to be E.g. how did mammals evolve from ancestral reptiles (taxonomic group)

17. Speculative, but not a leap of Faith

18. Phylogenic web quest! Go get a copy of the web quest for you and your partner (or just you if you are working alone) Answer all of the questions then continue this power point. Keep your web quest b/c you will be checking some of your answers. When you are done staple you and your partner’s (if you had a partner) copy together and put them in the bin. It should take 30 minutes or less! Watch your time.

19. We use Phylogenetic Trees to sort organisms A phylogenic tree is an evolutionary family tree. Uses physical traits and/or DNA

20. Note Thus the answer for web quest # 4 is that it does not matter. Either order means the same thing.

21. This DOES NOT say Salamanders and Humans are closely related

22. Phylogenic tree of Vertebrates

23. Tips for Making Trees Use your brain! Try and think, don’t just ask Trial and error, then double check – does your tree make sense?

24. There are a LOT of species Phylogenetic trees get really, really complicated and extremely detailed So…

25. The Taxonomic Groups is how we organize all the organisms on the Earth! Domain Kingdom Phylum Class Order Family Genus Species

26. Ex: Cat Taxonomy Domain – Kingdom Phylum – Class » Order Family Genus species Eukarya – Animalia Chordata – Mammalia » Carnivora Felidae Felis catus

27. Example Felis Catus Felis

28. Pneumonic Device Dude – Kings Play – Chess » On Fancy Gold Sets Or make your own!!!

29. Scientific Names are based on Taxonomy Genus species of taxonomy put together. Ex: humans are Homo sapiens/H. sapiens Ex: Domestic cat is Felis catus (also called Felis domesticus, Felis silvestrus)

30. So, phylogenetic trees give us the evolutionary history (the order/relationship) and taxonomy allows us to categorize the history (like the Dewey decimal system of all organisms). Macroevolution comes down to new species…

31. OK stop here! Now you need to pick up the Speciation Web Quest from the front of the room. You should work through this with your partner. When you are done staple you and your partner’s (if you had a partner) copy together and put them in the bin. Then come back to this power point If for some reason you are running low on time you can go through the rest of this power point at home. Remember to pick up your HW.

32. Post web quest! So, hopefully you have a pretty clear picture of speciation but the following slides are for your review

33. What is a species? – a group of interbreeding populations that are reproductively isolated from other groups Appearance can be misleading in determining a species.

34. Members of Different Species May Be Similar in Appearance Fig. 16-1

35. Members of SAME Species May Differ in Appearance Fig. 16-2

36. How Do New Species Form? Speciation is the process by which new species form – Speciation depends on two factors The isolation of populations must prevent gene flow and thus keep them similar Genetic divergence must occur, driven by genetic drift or natural selection

37. – the different pathways to speciation fall into two broad categories allopatric speciation, the isolating mechanism is a physical barrier sympatric speciation, isolation occurs without geographical separation

38. Geographical separation of a population can lead to allopatric speciation (as in the web quest example of island fruit flies) – Separation can be caused by: Geological changes such as: – Volcanoes – Earthquakes – continental drift – change of course by rivers – Allopatric speciation is believed to be the most common type of speciation, especially among animals

39. Part of a mainland population reaches to an isolated island Divergence may eventually become sufficient to cause reproductive isolation The isolated populations begin to diverge due to genetic drift and natural selection Allopatric Isolation and Divergence Fig. 16-9

40. Isolation without geographical separation can lead to sympatric speciation too! Sympatric speciation may occur when a geographical area contains two distinctly different habitats. Through natural selection, individuals of the species specialize in one habitat or the other Ex: apple vs. hawthorn tree

41. Part of a fly population that lives only on hawthorne trees moves to an apple tree The flies living on the apple tree do not encounter the flies living on the hawthorne tree, so the populations diverge Sympatric Isolation and Divergence Fig. 16-10

42. Now that we have defined a species & how they come about…how do we maintain a species?

43. Types of isolation? 1) Behavioral Isolation: occurs when two populations are capable of interbreeding but have differences in courtship rituals or other behaviors. Birds of Paradise! http://www.youtube.com/watch?v=nS1tEnfkk6M

44. 2) Geographic Isolation: occurs when two populations are separated by geographic barriers. Ex: Canyon, mountain, body of water. Salamanders http://video.pbs.org/video/1 300397304/ Watch this now http://www.teachersdomain.org/asset/rr10_vid_reproiso/

46. 3) Temporal Isolation: occurs when two populations reproduce at different times. Ex: orchids

47. Mechanical isolation: structure of reproductive organs is different enough that mating cannot occur.

48. Gametic isolation: gametes are incompatible – even if act of mating occurs, sperm cannot fertilize egg.

49. Hybrids…The Grey area This typically happens when a geographical barrier is removed. Animals that are closely related can mate and produce offspring. These offspring are typically sterile and/or weak A great example that works are mules. Strong and docile it’s a mix of the fragile horse (but easily trainable) and strong willed (but sturdy) donkey

51. The infamous Liger Fig. 16-8

52. There is also observed and experimental evidence of speciation. One example was in your web quest!

53. So, Darwin’s BIG IDEA was that natural selection takes place in populations that are isolated from one another and over LONG periods of time, small changes in allele frequencies from generation to generation can add up to BIG changes in species. This leads us again to the idea of a universal common ancestor.

54. We can represent this idea with a diagram like these. This only depicts MAJOR living categories of organisms and doesn’t even include extinct organisms and their relationships!

55. Extinction: Why do species disappear? Species have a cycle! 1. New species 2. Stable species w/ many sub species THIS can then lead to 1. new species OR 3. stable species with few sub species 4. reduction in range and numbers 5. extinction!

56. What Causes Extinction? Extinction is the death of all members of a species At least 99.9% of all species that ever existed are now extinct! WHA!!! The immediate cause of extinction is probably environmental change habitat destruction and increased competition among species

57. Small range Species inhabiting extremely limited ranges may become extinct if the area is disturbed The Devil’s Hole pupfish is found in only one spring-fed waterhole in the Nevada desert http://www.youtube.com/watch?v=R_dP4 ENjcL0 (watch at home) http://www.youtube.com/watch?v=R_dP4 ENjcL0 Wide-ranging species normally do not succumb to local environmental catastrophes

58. Very Localized Distribution Can Endanger a Species Fig. 16-13

59. Overspecialization – Species that develop adaptations that favor survival in a specific environment are at risk of becoming extinct The Karner blue butterfly feeds only on the blue lupine plant The habitat of the lupine has been significantly reduced by development Loss of the lupine will lead to extinction of the Karner blue butterfly Vs. The generalist species…like humans. We can adapt to many environments!

60. Extreme Specialization Places Species at Risk Fig. 16-14

61. Other species – Species that are unable to exploit resources more efficiently and effectively than their competitors may become extinct

62. Habitat change and destruction – Extinctions due to prehistoric habitat change have had a significant effect on the evolution of organisms – Human activities are the primary cause of present-day habitat destruction Clearing of tropical rainforests could lead to loss of up to half of all current species over the next 50 years

63. HW 1. Do a murkie: what you are confused about or what you thought was interesting today. 2. Pick up your HW. If there’s time you may start it in class. 3. Email me how it went. 4. Have a great day!