The Origin of Life 14.2

I. SPONTANEOUS GENERATION A. Belief that living things came from non-living things 1. Ex: Mold in my fridge came from the tomato it was found on 2. People believed this prior to the 1600’s

I. SPONTANEOUS GENERATION B. Francesco Redi disproved spontaneous generation of large organisms 1. See Pg. 401

I. SPONTANEOUS GENERATION C. Louis Pasteur disproved spontaneous generation of microorganisms using broth and different types of flasks. 1. Mid 1800’s

II. So How Did Living Things Form? A. Biogenesis- The idea that living things only come from other living things 1. Birth or Mitosis

II. So How Did Living Things Form? B. Primordial Soup Theory 1. Suggested by Alexander Oparin & John Haldane in Organic molecules (amino acids) could have formed from the gases in the primitive atmosphere

a) CO2 methane nitrogen +water vapor Amino Acids (simple organic molecules)

a)All living things contain carbon atoms (organic) b) Lightning could have caused chemical reactions in the atmosphere

II. So How Did Living Things Form? C. Urey & Miller, Re-created earth’s primitive atmosphere 2. Used electricity to imitate lightning 3. Simple organic compounds (amino acids) formed

II. So How Did Living Things Form? 4. Rain washed the amino acids into the oceans making “primordial soup” of the organic molecules 5. Small pools of water heated from the sun cause amino acids to link into protocells

II. So How Did Living Things Form? D. Protocell- Large, membraned structure that caries out some life processes such as cell division. E. From protocells came prokaryotes

III. The First Cells A. First prokaryotes were similar to today’s archaebacteria 1. Lived in extreme conditions 2. Most were heterotrophs

III. The First Cells 3. Some were capable of photosynthesis (autotrophs) a) cyanobacteria b) More oxygen in atmosphere created the ozone layer 2. Aerobic eukaryotes can now evolve

IV. Eukaryotes Evolve A. Endosymboint Theory (pg. 407) 1. A prokaryote ingested (ate) some aerobic bacteria (also prokaryotes) 2. The bacteria provides energy for the prokaryote

IV. Eukaryotes Evolve 3. These bacteria evolve into mitochondria creating an animal cell 4. Some prokaryotes also ingested cynobacteria that contained photosynthetic pigments that evolved into chloroplasts creating a plant cell