1. Opener…Wednesday!!! 12/16 Please list FIVE things you want to know about evolution & the history of the EARTH.

2. Ch 14: History of Life 14.1 Biogenesis

3. What’s BIO-GENESIS? All living things come from other living thingsAll living things come from other living things Wasn’t always thought this way...Wasn’t always thought this way...

4. Old Schoolers: Spontaneous Generation Living things arise from nonliving thingsLiving things arise from nonliving things TRUE?TRUE? NO!!!NO!!! Disproven by:Disproven by: –Redi –Spallanzani –Pasteur

5. Redi’s Expt

6. Spallanzani’s Expt

7. Pasteur’s Expt

8. Let’s Review!

9. Project Stuff due… Team Leaders—Team Leaders— –Collect your team’s work Mark them off your listMark them off your list Turn list in to meTurn list in to me –Make sure their name is on anything they turn in EVERYTHING must be emailed to me by 5pm todayEVERYTHING must be emailed to me by 5pm today –Exception: beach walkover stuff can be turned in Friday.

10. Want BioBucks? Want to put together the text and design for flyers and magnets?Want to put together the text and design for flyers and magnets? Need to make a couple different onesNeed to make a couple different ones See me at a break or end of classSee me at a break or end of class

11. 14-2: Earth’s History

12. What was EARLY EARTH like? VERY different conditionsVERY different conditions Hypotheses, testsHypotheses, tests

14. So, How Old is Earth? ~4 billion years~4 billion years –Look at the wall! How do we know?How do we know? Radiometric DatingRadiometric Dating

15. Radiometric Dating: how’s it work? Radioactive isotopesRadioactive isotopes Each: Specific rate of decay Each: Specific rate of decay Half-life: Time for ½ to decay to stable formHalf-life: Time for ½ to decay to stable form C-14 (radioactive) : C-12 (stable)C-14 (radioactive) : C-12 (stable) What are isotopes?? Half-life for C:Half-life for C: 5,730 years

16. 12.1 The Fossil Record 2. Radiometric dating uses decay of unstable isotopesuses decay of unstable isotopes Isotopes (different number of neutrons) have specific “half-lives”Isotopes (different number of neutrons) have specific “half-lives” Estimates an actual AGEEstimates an actual AGE neutrons protons 2 Ways to Age Fossils

17. Use Carbon-14 to Age Things < 60,000 yrs old

18. 12.1 The Fossil Record A half-life is the amount of time it takes for half of the isotope to decay.

19. An Example...

20. So...where and how did LIFE begin? Three main ideas –Organic molecule hypotheses –Early cell structure hypotheses –RNA as early genetic material

21. I. Organic molecule hypotheses Organic = ????Organic = ???? Elements in planet, so, how  organic?Elements in planet, so, how  organic? FIRST--FIRST-- Oparin & Haldane’s Hypothesis (1920s)Oparin & Haldane’s Hypothesis (1920s) –Early earth conditions –Ammonia, H gas, water vapor, hydrocarbons (methane)

22. What did they think happened? High tempsHigh temps Gases combine  simple org cmpdsGases combine  simple org cmpds –Amino acids Earth cooled, water condensation  lakes, etc & AAs gather thereEarth cooled, water condensation  lakes, etc & AAs gather there Lightning, UV catalyze chem rxnsLightning, UV catalyze chem rxns  macromolecules (proteins)  macromolecules (proteins) Didn’t do an expt....Didn’t do an expt....

23. Miller & Urey’s Expt (1953-based on Oparin & Haldane Hyp)(1953-based on Oparin & Haldane Hyp) Variety of organic cmpds produced!Variety of organic cmpds produced! Lots other researchers sinceLots other researchers since CO 2, O 2 interfere w/it...so, must not have been present, or happened under water.CO 2, O 2 interfere w/it...so, must not have been present, or happened under water.

25. Another Option Organic cmpds came from meteoritesOrganic cmpds came from meteorites

26. II. Early cell structure hypotheses How can you get cells from organic cmpds? Cell-like structures first! 2. Lipid membrane hypothesis: –Cell-like, but not cells –Microspheres proteinsproteins –Coacervates Lipid, AA, sugar dropletsLipid, AA, sugar droplets

27. 1. Iron-sulfide bubbles hypothesis

28. III. RNA as early genetic material Ribozymes: present today in unicellular euk’s present today in unicellular euk’s RNA that can catalyze reactions... even their own replication

30. Let’s Review!

31. Opener: Sure Happy It’s...Dec. 17 th !!! REVIEW...Summarize each experiment: Redi Spallanzani Pasteur

32. 14-3: Origin of Life

33. The Origin of Heredity Cells/life-forms must be able to replicate...WHY?Cells/life-forms must be able to replicate...WHY?

34. What’s a RIBOZYME? RNA that catalyzes a chem rxnRNA that catalyzes a chem rxn Also allows RNA to self-replicateAlso allows RNA to self-replicate “the RNA world”“the RNA world”...evidence that THIS may have been the 1 st genetic material!...evidence that THIS may have been the 1 st genetic material!

35. 3 Major Inferences about Early Earth: Little/no Oxygen gasLittle/no Oxygen gas Organic molecules “food” in the envtOrganic molecules “food” in the envt Oldest fossils of cells ~ bacterial sizeOldest fossils of cells ~ bacterial size Anaerobic, heterotrophic prokaryotesAnaerobic, heterotrophic prokaryotes

36. Diversity of Life Led to Competition for food...who came next? AUTOTROPHS!AUTOTROPHS! Likely chemoautotrophs...why?Likely chemoautotrophs...why? Example—Example— Archaea-harsh envtsArchaea-harsh envts

37. THEN came Photosynthesis: Evidence 1.Fossils 3.5 bya (cyanobacteria appeared)3.5 bya (cyanobacteria appeared) StromatolitesStromatolites

38. 2. Chemical Traces: Oxygen Harmful to many unicellular organismsHarmful to many unicellular organisms Some able to bind it...1st sign of aerobic respiration!Some able to bind it...1st sign of aerobic respiration! Built up in atmosphere (~bill yrs?)Built up in atmosphere (~bill yrs?) OzoneOzone

39. The First Prokaryotes Archaea Bacteria Eukaryotes Cyanobacteria Chloroplasts Mitochondria

40. First Eukaryotes What are differences b/w pro. & eukaryotes?What are differences b/w pro. & eukaryotes? May have developed from prokaryotes...May have developed from prokaryotes... Draw it!Draw it!

41. Endosymbiotic Theory MutualisticMutualistic EVIDENCE:EVIDENCE: Chloroplasts & mitochondria replicate independently of cell cycleChloroplasts & mitochondria replicate independently of cell cycle Own DNA, sim to prok & circularOwn DNA, sim to prok & circular

42. http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/60258.htm

44. REVIEW: True or False? The first cells must have been aerobic.The first cells must have been aerobic. FalseFalse RNA molecules are needed for protein synthesis.RNA molecules are needed for protein synthesis. TrueTrue Ozone in the upper atmosphere is poisonous to life.Ozone in the upper atmosphere is poisonous to life. FalseFalse

45. REVIEW: How’s RNA different from DNA?How’s RNA different from DNA? RNA diff shapes; some self-replicatingRNA diff shapes; some self-replicating What traits make archaebacteria likely relatives of Earth’s earliest organisms?What traits make archaebacteria likely relatives of Earth’s earliest organisms? Survive harsh envts, many anaerobic, chemoautotrophsSurvive harsh envts, many anaerobic, chemoautotrophs Difference between photosynthesis & chemosynthesis?Difference between photosynthesis & chemosynthesis? Energy from inorganics vs lightEnergy from inorganics vs light Explain the endosymbiotic theory.Explain the endosymbiotic theory. Primitive prok engulfed smaller proks. Which evolved into mitochondria and chloroplastsPrimitive prok engulfed smaller proks. Which evolved into mitochondria and chloroplasts

47. History of the Earth Video Clip