BIOL 1202 : Bio 1202-EXAM 1 NOTES
Document Summary
The history of life on earth- chapter 25. No spontaneous generation now, but must have happened then. Testable hypotheses: abiotic synthesis of small organic molecules, joining these molecules into polymers, packaging these molecules into protobionts , the origin of self-replicating molecules. Alternative hypotheses: first organic compounds may have been synthesized near hydrothermal vents, extraterrestrial origin. Small organic molecules polymerize when they are concentrated on hot sand or clay. Aggregates of abiotically produced molecules surrounded by a membrane. Liposomes can form when lipids or other organic molecules are added to water. Oxygen has a negative influence on the formation of complex organic molecules because it is highly reactive. The oldest known fossils contain traces of rna. Sedimentary strata reveal the relative ages of fossils. Fossil records shows great changes in organisms through time. Order of fossils in rock strata tells us the sequence in which they were laid down. Radioactive isotopes decay into a daughter isotope at a fixed rate.
