Evolution

1. Evolution The change in a population’s genetics over time

2. The history of Evolution • People first thought that life originated by spontaneous generation • Nonliving material gives rise to living material • i.e. that maggots and flies spontaneously appear in rotted food web.utk.edu/.../5rubrics/graphics/04_01.gif

3. History continued • Redi- tested the spontaneous generation hypothesis-1668 • Discovered that rotting meat does NOT produce maggots • Thought this only applied to large organisms, not microbes

4. History continued- mid 1800s • Pasteur- demonstrated that microorganisms are not spontaneously generated The Control: The Experiment:

5. Biogenesis • Living organisms can only come from other living organisms http://www.historyoftheuniverse.com/images/cell_division.gif http://www.kingsstilecottage.co.uk/images/lion-with-cubs.jpg

6. So… Where did life begin? • Oparin- hypothesized that life began in the ocean from organic molecules • Inorganic molecules from volcanoes and evaporation were in atmosphere • Lightning storms caused inorganic molecules to fuse – became organic • (C, H, O) • Rain washed organic molecules into ocean • Life began there http://southdakotapolitics.blogs.com/south_dakota_politics/images/2008/04/20/fertilization2.jpg

7. Miller and Urey • Tested Oparin’s hypothesis Lightning Atmosphere Rain Volcanoes Ocean

8. Miller and Urey • Discovered that organic molecules could be made from inorganic • Organic molecules were produced in the closed system

9. Endosymbiosis Theory Possible evolution of mitochondria (aerobic organisms) and chloroplasts (plants) http://faculty.ircc.edu/faculty/tfischer/images/endosymbiosis.jpg

10. Evolution Video

11. How do we know evolution happens?

12. Evidence for evolution It took Charles Darwin 2 decades to develop his theory of evolution What evidences did he look for? • Fossils-earliest record of life • Deep are simple, oldest • Shallow are complex, newest (in undisturbed rock layers) http://www.sculpturegallery.com/three/fossil_fish.jpg

13. Evidence for evolution • Anatomy: • Homologous Structures • Same structure, different function • Ex. Bones of human, whale, crocodile • Analogous Structures • Same function, different structures • Ex. Bird wings, butterfly wings • Vestigial Structures • Organ with no function today, but worked in the past • Ex. Pelvic bones in snake, hip bones in whale http://taggart.glg.msu.edu/isb200/HOMOL.GIF http://www.citruscollege.edu/pic/46/0345l.jpg http://www.answersingenesis.org/assets/images/articles/ee/v2/whale-vestigial-structure.jpg

14. Evidence for Evolution • Embryology • Study of developing fetus/baby • All vertebrates have some common characteristics • Ex. Tail bones, gill slits • Show common origins apps.carleton.edu/.../photostock/193602.jpg

15. Evidence for Evolution • Biochemistry • Compare DNA and proteins • More common points = close relationship Mimio Review http://www.blog.speculist.com/archives/gem-dna.jpg

16. Cladogram • Shows evolutionary relationships based on similarities: • In characteristics • DNA or amino acids • More in common = closer common ancestor

17. Results Copy into lab Notebook:Biochemical Evidence of Evolution Number of Differences in Amino Acid Sequences

18. Lab Questions/Analysis • Sketch a cladogram to show the evolutionary relationships • Which organism is most closely related to humans? • Explain how you determined this? • Briefly describe the process of using amino acid sequences or DNA to determine evolutionary relationships among organisms.

19. The Mechanism How Does Evolution Happen?

20. Lamarck- Inheritance of acquired characteristics • Organisms acquire adaptations during lifetime • Adapt because they have to • Use and disuse • Variation gained during lifetime • Giraffe’s neck got longer through use • Trait passed on to offspring

21. Does variation exist in a population or is it acquired through a lifetime? Let’s find out…

22. Problems with Lamarck Expected Actual Cut off mouse’s tail All offspring have tails!!! • Cut off mouse’s tail • Has offspring with no tail

23. Charles Darwin ~ 1831 • “Father of Evolution” • Studied in Galapagos Islands • Developed theory of evolution by natural selection • First to propose logical mechanism • Organisms with favorable traits will survive to reproduce and pass on traits to offspring

24. Darwin’s Giraffes • Variation already exists • Favorable adaptations = survival • Avg neck length increases with time

25. 4 aspects of Natural Selection • Overproduction – more offspring are born than can survive, not all survive • Variation – individuals in a population vary in characteristics • Competition – organisms with favorable variations survive and reproduce • Populations change – over time favorable traits (inherited traits) increase in a population

26. Natural selection • Populations evolve through natural selection • 3 main types of natural selection • Stabilizing selection • Directional selection • Disruptive selection

27. Stabilizing selection • Natural selection that favors the average individual

28. Directional selection • Favors one extreme variation of a trait • Ex. the giraffe with the longest neck maybe able to reach more food

29. Disruptive Selection • Both extreme variations are favorable • Ex. light and dark shells blend in, medium are seen and eaten

30. Variation Lab Purpose: Does variation exist in a population? You will be given 10 peanuts. Open the shells and measure each shell. Record the length (in millimeters) of each shell in the data table. We will make a tally sheet from each group for the class data table. Group Data Length in mm Class Data

31. Variation Lab Analysis Due to variation, we need a large sample size (class data). Analysis: • What is the largest peanut shell in the sample? • What is the smallest shell in the sample? • What is the mean value of shell lengths? • What is the mode of shell lengths? • Draw a bar graph of the results. Dependent variable is # of pods, Independent variable is pod size. • What is the shape of the curve over the bars of the graph? • What type of selection does this represent?

32. Adaptations the process or structure that enables organisms to become better suited to their environmentwww.doe.virginia.gov/VDOE/LFB/glossary/index.html http://www.lapshin.org/nikita/cacti/Echinocactus-grusonii2.jpg

33. Adaptations • Camouflage – ability to blend into surrounding environment http://3quarksdaily.blogs.com/3quarksdaily/images/wolfe_seal_1.jpg http://lpmpjogja.diknas.go.id/kc/a/animal/animal-camouflage-1.jpg

34. Adaptations • Mimicry - resembling another species or object to hide, for protection from predators http://abc-rags.tripod.com/Peru/StickInsect.JPG http://mrgrassosclass.com/images/mimicry.gif

35. Competition Activity Purpose: Does variation allow for success in competition for resources? Make a data table for your group and for the class data. Enter Data Here

36. Competition Activity Analysis • What strategy was used to get the most food? • What variation was best for each type of food? Use data to support your answer. • How does this relate to natural selection? • Competition - • Variation - • Overproduction –

37. How do new species form? • Speciation- the evolution of new species • Species can only reproduce with the same species to produce fertile offspring • 3 ways for speciation to occur • Geographic isolation • Reproductive isolation • Adaptive radiation www.bio.indiana.edu/.../broodxmovies/index.htm

38. Geographic Isolation • 2 populations separated by geography (river, mountain, etc.) • Cannot cross barrier • Stop reproducing  become 2 different species • Ex. mice separated by mountains Rocky Mountains

39. Reproductive Isolation • Can occur 2 different ways • populations become different in reproductive (courtship) behavior and stop reproducing • Incompatible DNA • Ex. songbirds with different or incomplete songs

40. Adaptive radiation • A common ancestor leads to many variations • Species fill many niches, cause divergent evolution • Ex. Galapagos finches Hawaiian birds Common Ancestor

41. Convergent Evolution • unrelated species have similar adaptations while living in different locations • Ex. Euphorbia and Organ Pipe cactus: cactus like plants share fleshy body types and no leaves (one in deserts of Africa, other in deserts of N. and S. America) http://www.milosh.net/photo/usa99/organ1.jpg http://cactiguide.com/graphics/x_noncacti_euphorbia_600.jpg

42. How fast does speciation occur? • 2 timeframes for speciation • Gradualism • Punctuated equilibrium • Both result in new species http://stowa.de/shop/pix/a/z/antea365/b1.jpg

43. Gradualism • Species originate gradually through a number of adaptations

44. Punctuated Equilibrium • Quick rapid bursts of change (adaptations) followed by periods of stability

45. Fishy Frequency Lab Purpose: Will gene frequencies change over time? p + q = 1

46. Fishy Frequency Lab Analysis • What happened to the frequency of the blue colored fish? Why? • What happened to the frequency of the clear colored fish? Why? • Which colored fish had the advantage (selected for)? Why? • How would Darwin have explained these results?