Origin of life


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Origin of life

  1. 1.  Earth is estimated to be about 4.6Earth is estimated to be about 4.6 billion years old.billion years old.  Atmosphere was very harsh.Atmosphere was very harsh.  Very hot.Very hot.  Lot’s of water vapor in the atmosphere.Lot’s of water vapor in the atmosphere.  Volcanic activity.Volcanic activity.  No breathable oxygen gas (CarbonNo breathable oxygen gas (Carbon dioxide, ammonia, hydrogen gas, weredioxide, ammonia, hydrogen gas, were present).present).
  2. 2. Origin of Life…Origin of Life…  Extraterrestrial TheoryExtraterrestrial Theory  Creationism TheoryCreationism Theory  Chemical EvolutionChemical Evolution Organic CompoundsOrganic Compounds
  3. 3. The Origin of Life’s Chemicals…The Origin of Life’s Chemicals…  All of life is composed of organicAll of life is composed of organic compounds (nucleic acids, proteins,compounds (nucleic acids, proteins, lipids, carbohydrates)lipids, carbohydrates)  In order for life to form, these buildingIn order for life to form, these building blocks had to be present.blocks had to be present.  Charles Darwin said that life probablyCharles Darwin said that life probably formed in a “warm little pond…”formed in a “warm little pond…”
  4. 4. The Origin of Life’s Chemicals…The Origin of Life’s Chemicals…  Once earth began to cool, oceans beganOnce earth began to cool, oceans began to form as water vapor condensed.to form as water vapor condensed.  Question: Could organic compounds haveQuestion: Could organic compounds have formed from material present on earlyformed from material present on early earth?earth?
  5. 5. Origin of Life’s ChemicalsOrigin of Life’s Chemicals  Miller-UreyMiller-Urey  GoalGoal:: Recreated atmosphere of Early Earth  ObjectiveObjective:: Can organic compounds form?  ResultsResults:: amino acids, nucleotides, lipids, carbohydrate pieces
  6. 6. Fossils and Ancient LifeFossils and Ancient Life  Paleontologists are scientists who studyPaleontologists are scientists who study fossils.fossils.  Fossil is any trace of an ancientFossil is any trace of an ancient organism.organism.  Ex) bones, feathers, footprints,Ex) bones, feathers, footprints, impressions, etc.impressions, etc.
  7. 7. MicrofossilsMicrofossils  Scientists had hardScientists had hard time findingtime finding evidence of firstevidence of first lifelife  Most ancient lifeMost ancient life was microscopicwas microscopic  StromatolitesStromatolites  3.5 Billion years old3.5 Billion years old  11stst life on earthlife on earth bacteria lived in seabacteria lived in sea
  8. 8. The Fossil RecordThe Fossil Record  Fossils occur in a particular order.Fossils occur in a particular order.  Certain fossils only occur in more recentCertain fossils only occur in more recent rock.rock.
  9. 9. How do fossils form?How do fossils form?  Not everythingNot everything fossilizes.fossilizes.  Certain conditions haveCertain conditions have to be perfect forto be perfect for fossilization to occur.fossilization to occur.  For every organism thatFor every organism that fossilizes, hundredsfossilizes, hundreds more die without amore die without a trace.trace.  Most fossils are foundMost fossils are found in “sedimentary” rock.in “sedimentary” rock.
  10. 10. Dating Fossils (Two methods)Dating Fossils (Two methods) 1.1. Relative DatingRelative Dating  Determining age ofDetermining age of fossil based on howfossil based on how deep it is buried.deep it is buried.  Placement is comparedPlacement is compared with other fossils andwith other fossils and age is determined.age is determined.  Oldest layers of rockOldest layers of rock at the bottomat the bottom  Relative dating allowsRelative dating allows you to compare ageyou to compare age one fossil to the next,one fossil to the next, but does not give anbut does not give an exact age to theexact age to the fossil.fossil.
  11. 11. Dating Fossils (two methods)Dating Fossils (two methods) 2.2. Radioactive DatingRadioactive Dating  Used to determine actual age of rockUsed to determine actual age of rock (fossils).(fossils).  Requires knowledge of chemistry and “half-Requires knowledge of chemistry and “half- life” of radioactive isotopes.life” of radioactive isotopes.
  12. 12. Road to Modern OrganismsRoad to Modern Organisms  Scientists believe earliest life was foundScientists believe earliest life was found in sea.in sea.  11stst life was unicellular, prokaryotic =life was unicellular, prokaryotic = bacteriabacteria  Photosynthesis changed Earth’sPhotosynthesis changed Earth’s atmosphere released Oatmosphere released O22 - cyanobacteria- cyanobacteria  Unicellular Eukaryotes – EndosymbioticUnicellular Eukaryotes – Endosymbiotic TheoryTheory  Multicellular organismsMulticellular organisms
  13. 13. Classification/EvolutionClassification/Evolution
  14. 14. Bacteria – unicellular,Bacteria – unicellular, prokaryoticprokaryotic
  15. 15. Protista – eukaryoticProtista – eukaryotic
  16. 16. Fungi- multicellular, eukaryoticFungi- multicellular, eukaryotic
  17. 17. Animals- multicellular,Animals- multicellular, eukaryoticeukaryotic
  18. 18. Plants- multicellular, eukaryoticPlants- multicellular, eukaryotic