Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Experiments to Disprove Abiogenesis or Spontaneous Generation
Document related concepts
no text concepts found
Transcript
Theories for Origin of Life Spontaneous generation or Abiogenesis Early theory that held that organisms originated from nonliving materials Generation of life from nonliving matter They spontaneously are alive. POOF they appear! Examples decaying meat produced maggots, mud produced fishes, and grain produced mice. Biogenesis Life comes from other living things Life originated from preexisting life Experiments to Disprove Abiogenesis or Spontaneous Generation Redi Experiment 1 Francisco Redi: use raw meat and jars to disprove abiogenesis. organisms did not arise by spontaneous generation or abiogenesis. Pasteur Experiment 2 Louis Pasteur: Designed an experiment using an S-shaped flask that disproved abiogenesis in microorganisms. Set up experiment in which air, but no microorganisms, was allowed to contact broth that contained nutrients. His experiment showed that microorganisms do not arise in the broth, even in the presence of air. Proved biogenesis that living organisms come from other living things. Oparin Early Atmosphere and Conditions on Earth In early 1920’s AI Oparin proposed that the atmosphere of the early Earth contained no oxygen. The atmosphere contained water vapor, carbon dioxide, nitrogen, methane and ammonia. Lightning strikes were probably more frequent in the early atmosphere. Conditions were favorable for the synthesis of organic molecules He hypothesized that life began in the oceans. Energy from the sun, lightening and Earth’s heat triggered chemical reactions to produce small organic molecules The rain probably washed the molecules into the oceans to form what is often called the primordial soup. Urey and Miller Stanley Miller and Harold Urey tested the hypothesis of Oparin. They simulated the conditions of early Earth by constructing an apparatus, which contained water, hydrogen, methane and ammonia (to simulate early atmosphere). The chemicals were heated (to simulate earth’s interval heat) and an electric charge (to simulate lightening) for a number of days. The Miller-Urey Experiments Amino acids were present in the water. The Evolution of Cells Endosymbiotic Theory: eukaryotes arose from photosynthetic and aerobic prokaryotes living inside of a larger prokaryote.
