Adaptation and Natural Selection

Rating:
Summary: An antiquated classic
Review: A brilliant book. But the dismissal of group selection, while at the time warrented, must be reevaluated in light of work done in the field. If you read Williams you also may want to look into David Sloan Willison.

Rating:
Summary: An antiquated classic
Review: A brilliant book. But the dismissal of group selection, while at the time warrented, must be reevaluated in light of work done in the field. If you read Williams you also may want to look into David Sloan Willison.

Rating:
Summary: The potency of natural selection is largely underestimated
Review: Another reader has already given an excellent summary of this book. I would like to stress only some important points in my comment.

One should have a rather good knowledge of basic algebra, statistics, botany and biology to fully understand this book.

This is a key text about Darwinism. Its influence cannot be overestimated, as show a few excerpts hereafter: 'there is nothing in the basic structure of the theory of natural selection that would suggest the idea of any kind of cumulative progress' and 'Evolution was a by-product of the maintenance of adaptation'.
These sentences are cornerstones of today's theories on Darwinism (see the works of the late S.J. Gould or Richard Dawkins).

In a cool style, but with compelling arguments, the author wipes the floor with his opponents' theories about group adaptations, instead of adaptations on the individual level.
He also stresses the fundamentally different roles of male and female mammals for the production of offspring and the evolutionary impact of female choice.

But there is more: (adapted sentence)'If some organisms were not entirely self-seeking, they, and Nature in general, would be more ethically acceptable. In most theological systems it is necessary that the creator be benevolent and that this benevolence is shown in his creation. If Nature is found to be malicious or morally indifferent, the creator is presumably too. For many, peace in mind might be difficult with the acceptance of these conclusions, but this is hardly a basis for making decisions in biology'.
This sentence is still today too big a swallow for the moral elite, unable to comprehend their own Darwinian behaviour and unable to think about the fact that 'natural selection, albeit stupid, is a story of unending arms races, slaughter and suffering' (G.C. Williams in 'Plan and Purpose in Nature').

An essential book by a superb free mind.

Rating:
Summary: 'Adaptation and Natural Selection' Précis
Review: The significance of George C. Williams analysis in "Adaptation and Natural Selection" lies in his detailed argument of why natural selection functions on the level of the individual and not the group. His defense of Darwinism rewrites the generally held assumption that adaptation characterizes species and populations, and emphasizes the role that natural selection plays in shaping the individual genotype. He thus makes possible the explanation of evolution without the use of terms such as 'group selection,' 'population adaptation,' or 'progress.' While Williams acknowledges that group selection plays a significant role in some of earth's biota, such as the eukaryotes, individual selection characterizes most organisms which reproduce sexually (xii). In the process of showing why individual selection vis a vis group selection is significant, Williams also, significantly, argues that the term adaptation cannot yet be understood in terms of any principles or procedures.

The significance of Williams' starting point - a clarification of what an adaptation is and isn't - is definitional. An evolutionary 'adaptation' has specific meanings: 1) Adaptations should only be called 'functions' when shaped by design and not chance (8); 2) the level of organization of an adaptation shouldn't be higher than that admitted by the evidence (19); 3) only natural selection could have given rise to adaptations (8). Thus the scientific study of an adaptation awaits more developments in biology.

Williams argues that natural selection operates and is effective only at levels measured statistically (22), for example, in terms of rates of random change, quantitative relationships among sampling errors, and selection coefficients (37). Mendelian populations selected for at the level of alleles exclusively meet these requirements (24). For Williams, natural selection of alternative alleles operates to choose between worse and better options at the level of individuals in a population (45).

Genetic, somatic and ecological factors, i.e. the environment, contribute to selecting for genes. Thus, environmental factors don't directly affect populations (58).

Williams identifies processes relating to the genetic system, such as sex-determining mechanisms (156), stability of genes (138), diploidy (126), introgressive hybridization (144), and the way sexual and asexual reproduction in the life cycles are distributed in the life-cycle (133) as short-term adaptations. Group survival, therefore, is a chance consequence of the these adaptations, as well as related errors such as mutation and introgression. In chapter 5, Williams also suggests that decent evidence does not exist for other mechanisms of evolutionary change or other genetic system adaptations, thus highlighting the exclusive role of natural selection in shaping life.

Reproductive physiological variations of organisms seem designed to maximize organisms' reproductive success. Instances such as unbridled fecundity (161) and sex differences in reproductive strategies all suggest that an individual organism's reproductive strategy is oriented to replicating its own genetic information and not the groups' or the populations'.

The significance of Williams' analysis of social adaptations (193) suggests that the benefits of cooperative social adaptations leading to cooperative relations among related individuals rest on a genetic basis; cooperation with individuals of alternative genetic information is less significant. For Williams, therefore, benefits to groups are consequences of incidental statistics; harmful group effects may accumulate in a similar way.

Williams concludes (251) by arguing that there are no established guidelines to answer the question "What is the function of an adaptation?" The approaches he outlines are significant because they lay the groundwork for further developments in biology to understand what an adaptation is in terms of individual selection.