Physical aspects of organic evolution

The system composed of species of living organisms and their environment evolves under a stream of available energy from the sun. The differential survival of the components depends on the degree of success of each in securing its share of energy from this stream. This type of problem is familiar from the study of physicochemical systems in which the distribution and change in distribution of matter among specified components is examined in its relation to parameters of state. But whereas it is characteristic of physicochemical systems commonly considered that structure and mechanism play at most a subordinate role, in the study of organic evolution the structure and mechanical properties of the components, on which their aptitude for capturing energy depends, play the dominant role. Address delivered before the Symposium on Mathematical Biology held during the meeting of the A.A.A.S. in Chicago, December 26–27, 1947. Other papers presented at the Symposium are also being published inThe Bulletin. Those include: Rapoport, Anatol and Shimbel, Alfonso. 9, 169, 1947; Culbertson, J. T.10, 31, 1948; Rapoport, Anatol and Shimbel, Alfonso.10, 41, 1948; Hearon, John Z.10, 175, 1948; Morales, Manuel F. and Smith, Robert E.10, 191, 1948. For technical reasons the papers are not published in the same order as they were presented. A complete list of the papers presented at the Symposium on Mathematical Biology, together with abstracts is published inBiometrics,4, No. 2, 1948.Editor.