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How Life Began

How Life Began

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How Life Began

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  1. How Life Began http://cmex.ihmc.us/VikingCD/Puzzle/Evolife.htm

  2. 1. Physical and Chemical Characteristics • A. Early atmosphere was thicker with carbon dioxide and red in color. • B. The ocean was olive in color • C. Great Bombardment Asteroid/meteorite bombardment created harsh conditions http://www.physicsoftheuniverse.com/topics_life_early.html

  3. 2. Early Environment Survivor- Mexican Cave Analogy Chemosynthetic bacteria: use Hydrogen Sulfide for energy source; survives in snotites or in phlemballs. http://www.caveslime.org/Photos/Snottites

  4. 3. Carbon • A. Basis of living things. • B. Bonds to form diverse compounds. • C. Miller’s experiment- amino acids that contain carbon formed in harsh conditions similar to early Earth. • D. Old rocks in Greenland contain carbon. http://www.geus.dk/viden_om/voii/ilulissat-uk/voii05-uk.html

  5. 4. Great Bombardment • A. Asteroid and comet bombardment • B. Tons of dust from the Universe bombards Earth. • C. Dust contains carbon, elements, compounds and minerals. • D. The building blocks of life, amino acids, form then peptides/protein. • E. Collision Simulation Experiment- amino acids survived force similar to comet impact and fused to form larger molecules or peptides.

  6. 5. Environments where life could be protected from great bombardment • A. Underground- microbes live in dark places and use chemicals like methane, propane, and ethane, for food and energy: chemosynthesis. • B. Deep ocean- microbes live on chemicals like Hydrogen Sulfide for food and energy: chemosynthesis.

  7. Amino acids, peptides, and proteins www.chemicalconnection.org.uk commons.wikimedia.org www.sigmaaldrich.com

  8. 6. Environment less hostile due to decreased bombardment • A. Bacteria moved to shallow ocean and used Sun’s light energy, carbon dioxide and water to make food and release oxygen: photosyntheticbacteria. • B. Bacteria evidence found in stromatolites, the oldest fossils. • C. Cyanobacteria: first to use photosynthesis, releaseoxygen as a waste product. • D. Oxygen absorbed into oceans and combined with iron to form oxides. • E. Cyanobacteriastarts the increase of oxygen from 1% to 21% (today), allows diversity of life, forms O3 (ozone) which provides a protective layer vs. UV.

  9. Cyanobacteria http://www.uni-frankfurt.de/%7eschauder/cyanos/cyanos.html http://commons.wikimedia.org/wiki/File:Efflorescence_verte_4_Cyanobacteria

  10. Stromatolites www.aslo.org http://www.sharkbay.wa.gov.au/tourism/what_to_see_and_do/ http://www.geology.sdsu.edu/seminars/fall08/10_29_08.html

  11. Iron ore http://www.constructionweekonline.com/article-9234-qatar-steel-secures-long-term-iron-ore-supply/

  12. Order of Events of How Life Began • Solar Nebula • Accretion • Bombardment • Radioactive decay • Iron Catastrophe • Magnetic Field • Volcanoes • Plantesimal hits Earth- tilt • Moon moves away • Water on surface, crust forms • Great Bombardment • Chemosynthetic bacteria • Great bombardment ends • Photosynthetic bacteria form; cyanobacteria

  13. Order of appearance of living things on Earth • 4 elements- C, O, N, H • Amino acids • Peptides • Proteins • Microbes-chemosynthetic • Cyanobacteria- photosynthetic • Multicellular organisms • Plants • Fish • Insects • Reptiles • Dinosaurs • Primates • First humans