Calvin joined the faculty at the University of California, Berkeley, in 1937 and was promoted to Professor of Chemistry in 1947. Using the carbon-14 isotope as a tracer, Calvin, Andrew Benson and James Bassham mapped the complete route that carbon travels through a plant during photosynthesis, starting from its absorption as atmospheric carbon dioxide to its conversion into carbohydrates and other organic compounds. In doing so, Calvin, Benson and Bassham showed that sunlight acts on the chlorophyll in a plant to fuel the Manufacturing of organic compounds, rather than on carbon dioxide as was previously believed. Calvin was the sole recipient of the 1961 Nobel Prize for Chemistry for what is sometimes known as the Calvin–Benson–Bassham Cycle. Calvin wrote an autobiography three decades later titled Following the Trail of Light: A Scientific Odyssey. During the 1950s he was among the first members of the Society for General Systems Research. In 1963 he was given the additional title of Professor of Molecular Biology. He was founder and Director of the Laboratory of Chemical Biodynamics and simultaneously Associate Director of Berkeley Radiation Laboratory, where he conducted much of his research until his retirement in 1980. In his final years of active research, he studied the use of oil-producing plants as renewable sources of Energy. He also spent many years testing the chemical evolution of life and wrote a book on the subject that was published in 1969.