Biological evolution: From basics to extended synthesis

In order to understand social evolution, we have to start with biological evolution, simply because the first coherent and mostly correct theory of evolution came to exist in biological evolution (Darwin 1859).This chapter therefore provides readers with some essential understanding of biological evolution, assuming no prior knowledge of the subject. The central goal of this chapter is to prepare the ground for Chapter 3, in which I shall stress that social evolution, despite building upon the foundation provided by biological evolution of our species, is much more complex than and very different from biological evolution.

The rest of the chapter is structured as follows. The second section provides a brief history of evolutionary thinking toward living things and human society.¹ The third section sorts out several notions of evolution in the social sciences literature and emphasizes that some notions are unnecessary and even misleading.The fourth section provides a brief introduction to the modern understanding of biological evolution, known as the “Modern Synthesis” or Neo-Darwinism.The fifth section highlights some recent discoveries in biological evolution that have made it abundantly clear that the Modern Synthesis does not fully capture the complexities and wonders of biological evolution. As a result, evolutionary theorization may have to move toward an “Extended Evolutionary Synthesis.” Together, Sections IV and V set a baseline for understanding social evolution and, more importantly, foreshadow the argument that understanding social evolution requires more than (Neo-)Dar-winism, whether generalized or not. The sixth section singles out some of the most common misunderstandings about biological evolution, many of which informed misapplications of evolutionary thinking to human society (detailed critique of these misapplications is postponed to Chapter 5, for the sake of flow). A brief conclusion follows.

A brief history of evolutionary thinking

One can certainly argue that the very first idea of evolution was the recognition that things around us do change, first articulated by Heraclitus in ancient Greece and Lao Tzu in ancient China around the sixth to fifth century BC. After admitting change, it is only natural for humans to ponder the “laws” and causes of change. In light of the imposing “beauty” of the world around us (e.g., the regularity of stars’ and planets’ movements and different species’ adaptations to their environments), the first but (understandably) false answer to this question of change had been a Creationist one that was first systematically stated in the Bible but could also be found in ancient Chinese, Egyptian, and Greek mythologies. Hence, as Mayr (1972a, 986—988) noted, for a very long time, one was either a statist or a Creationist, and the third possibility (i.e., evolution) was never seriously entertained by some of the most prominent figures in geology and biology' (e.g., Lyell, Agassiz, and Cuvier), even as late as the 18th and early 19th centuries (Mayr 1982, Chapter 8; Bowler 2003; see Table 2.1 for a summary).

In 1809, the French naturalist Jean-Baptiste Lamarck (1809 [1963]) formulated the first proto-theory of biological evolution. Although Lamarck’s theory rested upon an untenable foundation (see Section IV of this chapter), his theory was a milestone in the history of evolutionary thinking and paved ground for Darwin’s theory (Mayr 1972b, 1982, Chapter 8). Built upon Lamarck’s theory,Thomas Malthus’s (1798) treatise on population, and his own extensive field work with The Beagle, Darwin (1859) came to identify “natural selection” as part of the central mechanism of evolution through which species come to adapt to the environment.² Alfred A. Wallace independently came to grasp the central mechanism, although with much less rigor and detail than Darwin had.

Despite being a revolutionary' achievement, Darwin’s magnum opus provided only an incomplete account of biological evolution, mostly because much of the genetic and molecular basis of biological evolution was unknown in his time. Most notably, neither Darwin’s theory nor Lamarck’s includes a genetic and molecular mechanism of inheritance. ’ This mechanism would remain mostly unknown until the discovery of the deoxyribonucleic acid (DNA) double helix by James Watson and Francis Crick (1953). Indeed, Darwin (1859) did not explain the origin of species per se; he merely explained the adaptation of species to environment and thus only part of the story of speciation. The puzzle of origins of species remained mostly unsolved until the “Modern Synthesis” came along. Moreover, Darwin did not rule out the possibility of “direct inheritance of phenotypes without going through genetic materials” (hereafter, DIP-WGM).⁴

The problem of the origin of species and a host of other problems were mostly (but still incompletely) solved by the coming of the Modern Synthesis, jointly achieved by Thedosius Dobzhansky, Ernst Mayr, and others in the 1930— 40s. The rediscovery of Gregor Mendel’s work on genetics independently by Hugo de Vires and Carl Correns in 1890-1900s,’ the study of genes in Drosophila

TABLE 2.1 Theories of Natural and Social Change

melanogaster (i.e.,“the fruit fly”) by Thomas H. Morgan and his associates (Hermann J. Muller, Dobzhansky, and many others) in the 1910-30s, and finally the discovery of the DNA double helix by James Watson and Francis Crick in 1953 revealed some of the key secrets of biological evolution. Today, the core principles of biological evolution have been firmly established beyond any reasonable doubt (if one believes in the basic logic of modern science), and this whole body of theory on biological evolution is popularly known as “Neo-Darwinism,” to differentiate it from Darwin’s original, incomplete theory (which is known simply as “Darwinism”).⁶

Yet, the complexity of biological evolution still brings us plenty of surprises, and we may be approaching a more inclusive synthesis of biological evolution known as the “Extended Synthesis/Extended Theory of Evolution” (for details, see Section V of this chapter) ,⁷