Entropy, Ecology and Evolution: Toward a Unified Philosophy of Biology

Abstract

Darwin proposed that the capacity of organisms to produce more offspring that can be supported by the environment would lead to a struggle for existence, and individuals that are most fit for survival and reproduction would be selected through natural selection. Ecology is the science that studies the interaction between organisms and their environment within the context of Darwinian evolution, and an ecosystem is defined as a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. One topic that has been very much understudied and largely ignored in evolutionary biology is the overarching context of thermodynamics in controlling all biological processes and the evolution of life. Most fundamentally, organisms are self-replicating dissipative structures. Evolution is the process whereby variation in the structure of organisms have differential fitness in terms of their effectiveness at building and maintaining their structure, efficiently consuming free energy, and effectively reproducing and passing on those heritable variations, leading to change in the frequency of genetic variation and associated change in the characteristics in the population. The central process is dissipation of free energy according to the second law of thermodynamics, and evolution therefore is better conceptualized as the emergence of self-replicating dissipative structures that through natural selection become increasingly more efficient at degrading free energy. Ecosystems are linked series of dissipative structures with heat engine dynamics driven by random dissipation of energy and increasing entropy. The structure and composition of ecosystems across scales are emergent dissipative structures driven by the flow of energy and the increase in entropy. Communities and ecosystems are emergent properties of a system that has evolved to most efficiently dissipate energy and increase entropy. By focusing on the fundamental entity (energy), and the fundamental process (dissipation and disordering of energy and increasing of entropy), we are able to have a much clearer and powerful understanding of what life is, from the level of biochemistry, to evolution, to the nature of the organism itself, and to the emergent structures of ecosystems, food webs and communities.