2. Updated November 2004 Created by C. Ippolito December 2001 Origin of Life Chapter 4 pages 67 -87

3. Updated November 2004 Created by C. Ippolito December 2001 Question? Where does life come from? The ancient Greeks first asked this question. They devised two possible answers:

4. Updated November 2004 Created by C. Ippolito December 2001 Abiogenesis Belief that living things could arise from nonliving materials. –a.k.a. “spontaneous generation” Many examples:

5. Updated November 2004 Created by C. Ippolito December 2001 People believed maggots are formed from old meat mice can form from dirty shirts, water, and wheat hidden in a closet frogs come from mud

6. Updated November 2004 Created by C. Ippolito December 2001 Active Principle Aristotle proposed that an active principle brought life to nonliving materials. –Human get it from parents –Maggots get it from air –Frogs get it from sunlight, warmth

7. Updated November 2004 Created by C. Ippolito December 2001 Biogenesis Belief that living things could only come from other living things. –Francisco Redi, a 17th century scientist tried to prove this

8. Updated November 2004 Created by C. Ippolito December 2001 Francisco Redi Maggots from flies.

9. Updated November 2004 Created by C. Ippolito December 2001 Redi’s Hypothesis Maggots on meat come from another living thing. Redi noticed flies around decaying meat, so he proposed that maggots were related to the flies

10. Updated November 2004 Created by C. Ippolito December 2001 Redi’s Experiment Meat in open jar.  Maggots appear in jar.  Meat and maggots gone.  

11. Updated November 2004 Created by C. Ippolito December 2001 Conclusion of Time Meat became maggots which left to find food. To prove maggots were flies he repeated experiment by covering one jar after maggots appeared.

12. Updated November 2004 Created by C. Ippolito December 2001 Controlled Experiment  Control  Covered   Flies  appeared

13. Updated November 2004 Created by C. Ippolito December 2001 Redi’s Conclusion Maggots are immature flies that use meat as food. He now proves that flies leave something on meat to form maggots.

14. Updated November 2004 Created by C. Ippolito December 2001 Another Experiment

15. Updated November 2004 Created by C. Ippolito December 2001 Biogenesis accepted Redi’s work convinced scientists that biogenesis was true. –Leeuwenhoek discovers “animalicules” in water with his simple microscope Abiogenesis was in vogue again

16. Updated November 2004 Created by C. Ippolito December 2001 Needham Vs. Spallanzani Broth becomes microbes.

17. Updated November 2004 Created by C. Ippolito December 2001 Needham Believed in abiogenesis: Êboiled broth to kill microbes Ëcorked flasks to stop life in Ìcork allowed air the “vital principle” in

18. Updated November 2004 Created by C. Ippolito December 2001 Needham Experiment fresh broth  boiled broth  corked broth  its alive 

19. Updated November 2004 Created by C. Ippolito December 2001 Spallanzani Believed in biogenesis: Êdidn’t boil long enough to kill Ëcork too porous; new life in

20. Updated November 2004 Created by C. Ippolito December 2001 Spallanzani Experiment short boil  cork  its alive 

21. Updated November 2004 Created by C. Ippolito December 2001 Spallanzani Experiment short boil  melted  its alive 

22. Updated November 2004 Created by C. Ippolito December 2001 Spallanzani Experiment long boil  melted  not alive 

23. Updated November 2004 Created by C. Ippolito December 2001 Conclusion Some of Spallanzani’s flasks are still free of life. Abiogenesis believes said he did not let “vital principle” in He and Leeuwenhoek felt spores enter with air

24. Updated November 2004 Created by C. Ippolito December 2001 Louis Pasteur Late 1800’s finally disproved abiogenesis by allowing air into jar but keeping spores out. He did this with his “Swan Necked Flask”

25. Updated November 2004 Created by C. Ippolito December 2001 Swan Neck Flask Thin narrow curves allow air through but was narrow enough to trap spores. boiled  no life 

26. Updated November 2004 Created by C. Ippolito December 2001 Swan Necked Flask Tilting fluid into neck proved spores were caught. no life  life 

27. Updated November 2004 Created by C. Ippolito December 2001 Biogenesis true Does all life have a common ancestor? Where did very first life originate? Three hypotheses were considered:

28. Updated November 2004 Created by C. Ippolito December 2001  Supernatural All powerful God created life –found in all cultures’ mythology –no way to prove or disprove –not scientific creationism, scientific creationismcreationism, scientific creationism

29. Updated November 2004 Created by C. Ippolito December 2001  Exobiological View Life, like matter & energy always existed. –It arrived from outer space as spores –Plausible but how did life start out there.

30. Updated November 2004 Created by C. Ippolito December 2001  Chemosynthesis Life developed on Earth by natural processes. –Primitive Earth has all materials –Primitive Earth has proper conditions. Most “scientific” explanation

31. Updated November 2004 Created by C. Ippolito December 2001 Oparin Haldane Hypothesis Developed independently by two biochemists: –JohnHaldane –John Haldane - England –AlexanderOparin –Alexander Oparin - Russia BIG BANGHow life began after the BIG BANG.

32. Updated November 2004 Created by C. Ippolito December 2001 Known observations ¶Life composed of four (4) Major Classes of Complex Chemicals: 3proteins 3lipids 3carbohydrates 3nucleicacids 3nucleic acids

33. Updated November 2004 Created by C. Ippolito December 2001 More observations BUILDINGBLOCKS ·Complex chemicals composed of simpler BUILDING BLOCKS: 3proteins 3proteins - amino acids 3lipids 3lipids - fatty acids & glycerol 3carbohydrates 3carbohydrates - sugars 3nucleicacid 3nucleic acid - nucleotides

34. Updated November 2004 Created by C. Ippolito December 2001 More observations ¸Building blocks are composed of common elements: C H O N 3amino acids - C H O N C H O 3fatty acids & glycerol - C H O C H O 3sugars - C H O C H O N P 3nucleotides - C H O N P

35. Updated November 2004 Created by C. Ippolito December 2001 More observations ¹Universe began with a gigantic explosion that: ¹made simple gases ¹gases condensed and freeze ¹forming planets

36. Updated November 2004 Created by C. Ippolito December 2001 More observations ºPrimitiveatmosphere ºPrimitive Earth atmosphere different from today’s: 3ammonia 3ammonia - NH 3  3methane 3methane - CH 4  3watervapor 3water vapor - H 2 O 

37. Updated November 2004 Created by C. Ippolito December 2001 More observations »Abundantenergy »Abundant energy to combine gases: 3Heat 3Heat - from molten core & lava 3Steam 3Steam - water contact with lava 3Electrical 3Electrical - lightning in storms 3Radiant 3Radiant - UV & IR radiation of sun

38. Updated November 2004 Created by C. Ippolito December 2001 Chemical Evolution Energy causechemicalbonds ¬ Energy from heat, light, electricity, and radioactivity cause new chemical bonds to form between the gases; ­Stableremain ­Stable bonds remain; ®Unstablebreakdown ®Unstable bonds break down;

39. Updated November 2004 Created by C. Ippolito December 2001 Chemical Evolution Randombonds form buildingblocks ¯ Random formation of bonds in gases form the chemical building blocks; HotThinSoup °Building block condense in rains into the oceans forming a Hot Thin Soup;

40. Updated November 2004 Created by C. Ippolito December 2001 Chemical Evolution HotThinSoup sugarsfatty acidsglycerolaminoacids primitivenucleotides ± Hot Thin Soup - contains randomly formed sugars, fatty acids, glycerol, amino acids, and primitive nucleotides; ²Alternate heating and cooling with night and day causes further condensation and bonding;

41. Updated November 2004 Created by C. Ippolito December 2001 Chemical Evolution energy randomlyforms macromolecules ³ Continued input of energy randomly forms macromolecules from the building blocks; Hot ThickSoup ´The macromolecules condense into the oceans forming the Hot Thick Soup;

42. Updated November 2004 Created by C. Ippolito December 2001 Cellular Evolution HotThickSoup proteinslipidsnucleic acids carbohydrates À Hot Thick Soup - contains proteins, lipids, nucleic acids, and carbohydrates; coacervatesproteinoids ÁThese macromolecules aggregate to form cell like clusters of chemicals called coacervates or proteinoids;

43. Updated November 2004 Created by C. Ippolito December 2001 Heterotroph Evolution heterotrophs  “precells” use macromolecules in oceans for food, forming the first heterotrophs; fermentationcarbon dioxide ÃThese primitive organisms release free energy by process of fermentation releasing carbon dioxide (CO 2 ) into the atmosphere;

44. Updated November 2004 Created by C. Ippolito December 2001 Autotroph Evolution Ä Addition of CO 2 into atmosphere slows down random formation of molecules; ÅPrimitive organisms’ food in the oceans becomes scarcer; chlorophyll ÆCell clusters develop pigments like chlorophyll, that captures light

45. Updated November 2004 Created by C. Ippolito December 2001 Autotroph Evolution photosynthesis autotrophs Ç Cell clusters that capture light can now make their own food through photosynthesis forming the first autotrophs; ÈIn doing so these clusters add free oxygen (O 2 ) to the atmosphere;

46. Updated November 2004 Created by C. Ippolito December 2001 Autotroph Evolution ÉAtmospheric O 2 reduces mutating UV light penetration À  Scarcity of free sugar and presence of O 2 causes appearance of Respiratory Heterotrophs.

47. Updated November 2004 Created by C. Ippolito December 2001 Experimental Evidence Chapter 4 pages 73-80

48. Updated November 2004 Created by C. Ippolito December 2001 Experimental Evidence All of the Oparin-Haldane Hypothesis is based on observations available. Parts of the hypothesis have been verified by experimentation

49. Updated November 2004 Created by C. Ippolito December 2001 Urey Miller Experiment laboratory apparatus simulated the conditions of hot thin and hot thick soup

50. Updated November 2004 Created by C. Ippolito December 2001 Urey Miller Closed glass system, filled with water –ammonia and methane gases were pumped in –water heated, electrodes in gases gave sparks –Ultraviolet and infrared lamps shone on glass vessel –condenser used to cool gases system set up and allowed to run for a week.

51. Updated November 2004 Created by C. Ippolito December 2001 Urey Miller Apparatus  water heater  NH 3 CH 4   light electrode sparks  condenser   cold  warm

52. Updated November 2004 Created by C. Ippolito December 2001 Conclusion Scientists removed some fluid from the water and found: –simple amino acids and some simple sugars were in the liquid at the bottom

53. Updated November 2004 Created by C. Ippolito December 2001 Fox Experiment Fox took material similar to those in Urey’s results –altered the pH as proposed in “puddle” of soup –coacervate aggregates were formed

54. Updated November 2004 Created by C. Ippolito December 2001 Woese Hypothesis Proposed that “pre-cells” formed as droplets on dust entering the atmosphere

55. Updated November 2004 Created by C. Ippolito December 2001 Cairns-Smith Hypothesis One problem not solved is reproduction Cairns-Smith proposes that naked crystals of clay can replicate and were the first to store information