[1] Chemical evolution of the organic molecules, biopolymers, and systems of chemical reactions needed to form the first cells; Took 1 billion years. Chemists have also conducted lab experiments showing how simple inorganic compounds believed to be in the earth?s early atmosphere might have reacted to produce amino acids, simple sugars, and other organic molecules used as building blocks for the proteins, complex carbohydrates, RNA, and DNA needed for life. [3] Biological evolution by natural selection involves the change in a population's genetic makeup through successive generations.. The development of genetic variability in a population occurs through mutations: random changes in the structure or number of DNA molecules in a