How Life Began

http://cmex.ihmc.us/VikingCD/Puzzle/Evolife.htm

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

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

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

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.

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.

Amino acids, peptides, and proteins

www.chemicalconnection.org.uk

www.sigmaaldrich.com

commons.wikimedia.org

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: photosynthetic bacteria.

• B. Bacteria evidence found in stromatolites, the oldest fossils.• C. Cyanobacteria: first to use photosynthesis, release oxygen

as a waste product.• D. Oxygen absorbed into oceans and combined with iron to

form oxides.• E. Cyanobacteria starts the increase of oxygen from 1% to

21% (today), allows diversity of life, forms O3 (ozone) which provides a protective layer vs. UV.

Cyanobacteria

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

Stromatoliteswww.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

Iron ore

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

Order of Events of How Life Began1. Solar Nebula2. Accretion3. Bombardment4. Radioactive decay5. Iron Catastrophe6. Magnetic Field7. Volcanoes8. Plantesimal hits Earth- tilt9. Moon moves away10. Water on surface, crust forms11. Great Bombardment12. Chemosynthetic bacteria13. Great bombardment ends14. Photosynthetic bacteria form; cyanobacteria

Order of appearance of living things on Earth

1. 4 elements- C, O, N, H2. Amino acids3. Peptides4. Proteins5. Microbes-chemosynthetic6. Cyanobacteria- photosynthetic7. Multicellular organisms8. Plants9. Fish10. Insects11. Reptiles12. Dinosaurs13. Primates14. First humans