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Origin of Life

Origin of Life. Redi’s Experiment. Challenged the idea of spontaneous generation (SP: belief that life came from nonliving things) proved that flies laid the eggs that caused other flies. SPALLANZANI’S EXPERIMENT. hypothesized that microorganisms

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Origin of Life

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  1. Origin of Life

  2. Redi’s Experiment • Challenged the idea of spontaneous generation • (SP: belief that life came from nonliving things) • proved that flies laid the eggs that caused other flies

  3. SPALLANZANI’SEXPERIMENT • hypothesized that microorganisms formed from other microorganisms. (not from SP) • boiled broth became contaminated only when microorganisms from the air entered the flask.

  4. Pasteur’s Experiment • Placed broth in flasks w/ curved neck • T0 prevented microorganisms, from entering • Broth boiled inside remained clear for up to a year. • When the curved necks was broken off, the broth became contaminated w/ microorganisms • Settled the debate: spontaneous generation did not occur

  5. Topic: Biogenesis #1Date: 12-7-09 • What is spontaneous generation? • Who was the first to question spontaneous generation? • Describe his experiment. • Who finally disproved spontaneous generation?

  6. History of Life…theory • Cells may evolve and change, but new cells always arise from existing cells. How, then, did the first cells originate? • scientists attempt to reconstruct the processes that gave rise to the first cellular life.

  7. Earths Age: • 4.6 billion years old • Was made from studying layers of sediment in Earth’s crust. • Radioactive dating is also used to determine the age of Earth

  8. RADIOACTIVE DECAY • Can date objects • Ex. Ages of fossils and rocks can be determined by measuring the amount of radioactive decay that has occurred

  9. 1st organic compounds Oparin: • early atmosphere consisted of: NH3, H2; H2O, and compounds made of hydrogen and carbon, such as methane, CH4. • Energy from lightening caused a rxn to form early proteins

  10. Miller and Urey’s Apparatus Miller and Urey’s • Tested Oparin’s theory • Used apparatus containing similar chemical makeup of the atmosphere • Added electricity • Organic compounds formed: Nucleic acids, ATP, amino acids

  11. Cell Like Structures • Under early Earth conditions, membrane-bound structures have been formed in the laboratory • these structures may have replicated molecules of RNA • Believed to be the 1st cells

  12. First Prokaryotes • Because there was no O2, the 1st organisms were: • Anaerobic • Prokaryotes • Heterotrophs

  13. The 1st Autotrophs Chemosynthesis: • Ex. Archaebacteria • Live in harsh conditions • Use CO2 for food

  14. 1st Eukaryotes • Through endosymbiosis (mutually beneficial relationship) small prokaryotes fused w/ lger prokaryotes • Believed to be the 1st organelles such as mitochondria and chloroplasts • The “organelles” carried out aerobic respiration and contained DNA

  15. Topic: Biogenesis #2 • How old is Earth believed to be? • Explain the difference b/w radioactive and Carbon dating. • Who was the first to create organic compounds from inorganic compounds? • What is endosymbiosis?

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