BIO 182 Lecture Notes - Lecture 4: Abiogenesis, Tide Pool, Heterotroph
Document Summary
Early earth: 4. 6 billion years ago, no free oxygen, mostly nitrogen, methane, and carbon dioxide, high energy, intense volcanoes, very warm environment. Abiogenesis steps: synthesis of organic monomers from inorganic molecules, organic monomers to organic polymers, protobionts form organic molecules surrounded by membrane-like structure, heredity pass instructions to offspring. Rna probably came before dna since it can remember instructions as well as serve the purpose of proteins. Dna eventually replaced rna since dna can be stored in the nucleus and isn"t lost every time proteins are made which happens when rna changes to protein and rna is more susceptible to mutations. Abiogenesis probably occurred in hydrothermal vents or tide pools (possibly from an asteroid that crashed into earth) Heterotrophs carbon from organic molecules: chemoheterotrophs energy from chemical compounds, photoheterotrophs energy from light. Evolution of prokaryotes: absorptive anaerobic heterotrophs, anaerobic autotrophs non-oxygen photosynthesis, anaerobic ingestive heterotrophs eat to get energy, aerobic autotrophs oxygenic photosynthesis, aerobic heterotrophs.
