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The origins of Life

The origins of Life. Origin of the Solar System. Earth is estimated to be ~4.6 bill. yr old Evidence: Radiometric dating of rocks & meteors Nebula Hypothesis: Nebula: cloud of gas & dust in space Gravity pulled much material together (forming the Sun)

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The origins of Life

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  1. The origins of Life

  2. Origin of the Solar System • Earth is estimated to be ~4.6 bill. yr old • Evidence: Radiometric dating of rocks & meteors • Nebula Hypothesis: • Nebula: cloud of gas & dust in space • Gravity pulled much material together (forming the Sun) • Planets formed from remaining materials

  3. Ancient Earth What was it like? • Atmosphere contents: • Ammonia, H2O vapor, Methane (CH4), CO2 • Climate: • Extreme heat due to meteor impacts & volcanic activity • Eventually Cooling: Water vapor condensed (oceans formed) Click on picture to play video clip

  4. Organic Molecules 1. Miller - Urey Experiment • Hypothesis: Energy from lightning created organic materials from inorganic ingredients • Experimental Set-Up: • Ammonia, H2O vapor, Methane, CO gases added • Electricity added (simulate lightning) • Result: Amino Acids & later nucleotides were created

  5. 2. Meteorite Hypothesis • Hypothesis: Amino acids may have arrived on Earth through meteorite or asteroid impacts. • Fun Fact! 90 amino acids were found from this meteorite, only 19 of them can be found on Earth. Murchison Meteorite

  6. Early Cell Formation • Lipid membrane hypothesis • Liposomes • Spheres of lipids • Can form around organic molecules • Hypothesis: 1st cell membranes??????

  7. Early Genetic Material • A hypothesis proposes that RNA was the first genetic material. • Ribozymes are RNA molecules that catalyze their own replication. • DNA needs enzymes to replicate itself. • Because of this, scientists think that DNA evolved from RNA

  8. Eukaryotic Cell Formation • Endosymbiosis is a relationship in which one organism lives within the body of another. • Mitochondria and chloroplasts may have developed through endosymbiosis.

  9. Multicellular Life & Biodiversity • Evolution of sexual reproduction led to increased diversity/variation. • Sexual reproduction may have led to multicellular life.

  10. ReviewThese are questions that I would ask you on the test, so you should do your best at answering them accurately and completely. • What is a nebula? • What does the nebula hypothesis try to explain? • What materials/ingredients did Miller & Urey use in their experiment? Why these and not other ingredients? • Why was Miller and Urey’s experiment of great importance? • How did eukaryotic cells form? • How would sexual reproduction lead to diversity and multicellular life?

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