BLG 143 Lecture Notes - Lecture 1: Growth Medium, Cell Membrane, Cell Theory
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Are a product of evolution and continue to evolve as a population. All cells are made up of pre-existing cells: cell - highly organized; bounded by plasma membrane o. Life is sustained by chemical rxns that occur inside the cell: all cells descend from pre-existing cells and are connected by a common ancestry. Tested whether cells arise spontaneously or from other cells. Test 1: nutrient broth exposed to pre-existing cells cells from the outside could enter flask since the flask"s neck was straight o. Test 2: nutrient broth not exposed to pre-existing cells flask has swan neck that traps pre-existing cells due to the condensation caused by boiling -- cells cant grow in the broth proving that cells do not arise spontaneously. Individuals within a population vary in characteristics that are heritable. In a particular environment, versions of these characteristics help a population survive and/or reproduce better. Theory of evolution by natural selection: o.
