The Evolution of Complexity

TL;DR: Maynard Smith and Szathmâry's The Origins of Life is a concise and crisp account of how these kinds of major evolutionary transitions came about from the origins of genes to language.

Abstract: Since the late 19th century, evolutionists have focused on evidence for the origin of new forms in a genealogical branching tree. One could follow gradual changes in the beak of the finch as Darwin did, or study the anatomy of apes and humans as Huxley and Haeckel did. Yet, there is another kind of evolutionary change, no less important. In the process of evolution, there is both divergence and integration; there is divergence in the production of new life forms, but there is integration when these unlike entities unite so as to make new wholes. These unions are recognized today to be at the basis of some of the major steps in the evolution of life on earth: the origin of cells, of organelles, of other symbiotic associations, of multicellular organisms, populations, and communities. Maynard Smith and Szathmâry's The Origins of Life is a concise and crisp account of how these kinds of major evolutionary transitions came about from the origins of genes to language. It is driven essentially by two major themes: the division of labour, and the units of selection. Since the 19th century, the division of labour has been invoked to explain organic as well as human social progress. Developed in the socioeconomic theory of Adam Smith, the concept of division of labour was subsequently used by physiologist Henri Milne-Edwards to describe how the diverse organs of animals function for the good of the whole. Darwin then applied it to ecological relations between species when explaining divergence. Herbert Spencer, the most prominent 'social Darwinist', employed it to understand the entire world as a super-organism, exemplified by the reciprocal relations between plants