Robert N. Brandon

Adaptation and Environment

By focusing on the crucial role of environment in the process of adaptation, Robert Brandon clarifies definitions and principles so as to help make the argument of evolution by natural selection empirically testable. He proposes that natural selection is the process of differential reproduction resulting from differential adaptedness to a common selective environment.Originally published in 1990.The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

Individuality, Pluralism, and the Phylogenetic Species Concept

The concept of individuality as applied to species, an important advance in the philosophy of evolutionary biology, is nevertheless in need of refinement. Four important subparts of this concept must be recognized: spatial boundaries, temporal boundaries, integration, and cohesion. Not all species necessarily meet all of these. Two very different types of “pluralism” have been advocated with respect to species, only one of which is satisfactory. An often unrecognized distinction between “grouping” and “ranking” components of any species concept is necessary. A phylogenetic species concept is advocated that uses a (monistic) grouping criterion of monophyly in a cladistic sense, and a (pluralistic) ranking criterion based on those causal processes that are most important in producing and maintaining lineages in a particular case. Such causal processes can include actual interbreeding, selective constraints, and developmental canalization. The widespread use of the “biological species concept” is flawed for two reasons: because of a failure to distinguish grouping from ranking criteria and because of an unwarranted emphasis on the importance of interbreeding as a universal causal factor controlling evolutionary diversification. The potential to interbreed is not in itself a process; it is instead a result of a diversity of processes which result in shared selective environments and common developmental programs. These types of processes act in both sexual and asexual organisms, thus the phylogenetic species concept can reflect an underlying unity that the biological species concept can not.

Adaptation and evolutionary theory

The conception of adaptation was not introduced into biology in 1859, Rather what Darwin did was to offer a radically new type of explanation of adaptations and in so doing he altered the conception. As the above quotes indicate we have not in the last century sufficiently delimited this conception and it is important to do so. In this paper we will analyse and, I hope, clarify one aspect of the conception of adaptation. One of the aims of this paper is a theoretically adequate definition of relative adaptedness. As we will see such analysis cannot be divorced from an analysis of the structure of evolutionary theory. The other major aim of this paper is to expose this structure, to show how it differs from the standard philosophical models of scientific theories, and to defend this differentiating feature (and hence to show the inadequacy of certain views about the structure of scientific theories which purport to be con~plete).

From icons to symbols: Some speculations on the origins of language

This paper is divided into three sections. In the first section we offer a retooling of some traditional concepts, namely icons and symbols, which allows us to describe an evolutionary continuum of communication systems. The second section consists of an argument from theoretical biology. In it we explore the advantages and disadvantages of phenotypic plasticity. We argue that a range of the conditions that selectively favor phenotypic plasticity also favor a nongenetic transmission system that would allow for the inheritance of acquired characters. The first two sections are independent, the third depends on both of them. In it we offer an argument that human natural languages have just the features required of an ideal transmission mechanism under the conditions described in section 2.

Concepts and Methods in Evolutionary Biology

Introduction Part I: 1. Adaptation and evolutionary theory 2. Biological teleology: questions and explanations 3. A structural description of evolutionary theory 4. The levels of selection Part II: 5. Phenotypic plasticity, cultural transmission and human sociobiology 6. From icons to symbols: some speculations on the origins of language 7. Individuality, pluralism, and the phylogenetic species concept 8. The levels of selection: a hierarchy of interactors Part III: 9. Theory and experiment in evolutionary biology 10. The co-evolution of organism and environment 11. Reductionism versus holism versus mechanism References Index.

The Units of Selection Revisited: The Modules of Selection

Richard Lewontins (1970) early work on the “units” of selection initiated the conceptual and theoretical investigations that have led to the hierarchical perspective on selection that has reached near consensus status today. This paper explores other aspects of his work, work on what he termed “continuity” and “quasi-independence”, that connect to contemporary explorations of modularity in development and evolution. I characterize such modules and argue that they are the true units of selection in that they are what evolution by natural selection individuates, selects among, and transforms.

Does Biology Have Laws? The Experimental Evidence

In this paper I argue that we can best make sense of the practice of experimental evolutionary biology if we see it as investigating contingent, rather than lawlike, regularities. This understanding is contrasted with the experimental practice of certain areas of physics. However, this presents a problem for those who accept the Logical Positivist conception of law and its essential role in scientific explanation. I address this problem by arguing that the contingent regularities of evolutionary biology have a limited range of nomic necessity and a limited range of explanatory power even though they lack the unlimited projectibility that has been seen by some as a hallmark of scientific laws.

Genetic variation and environmental variation: expectations and experiments

Because the diversity of genetic systems (defined as those characteristics of the organism influencing the rate of genetic recombination) is much greater in plants than in animals, such systems have been of particular interest to students of plant evolution. Ever since the work of Darlington (1939), it has been realized that the evolutionary forces acting on genetic systems are likely to be different from those acting on more conventional morphological and physiological traits. For example, a particular chromosome number or recombination frequency may have very little direct impact on the physiological functioning of the organism, on its survival and fecundity, but may have a marked effect on the evolutionary potential of the descendants of that individual. As Stebbins (1950) states, ‘Hence in discussing the selective value of genetic systems we must consider primarily the advantages a particular system gives to the progeny of those who have it ... the immediate advantages or disadvantages of the system are of secondary importance.’ In the early works of Darlington, Huxley, Mather and Stebbins, the hypothesis was proposed that particular genetic systems result from a compromise between the need for constancy so as to preserve adaptation to the immediate contemporary environment and the need for flexibility in the face of changing environments to which the species will become exposed in the future. This idea was so forceful in its elegance and in its explanatory power that it became engrained in evolutionary biology more as a paradigm of how genetic systems actually do evolve, rather than as a hypothesis requiring rigorous formulation and testing.

Biological teleology: Questions and explanations

Abstract This paper gives an account of evolutionary explanations in biology. Briefly, the explanations I am primarily concerned with are explanations of adaptations . (‘Adaptation’ is a technical term and defining it requires a fairly lengthy digression.) These explanations are contrasted with other nonteleological evolutionary explanations. The distinction is made by distinguishing the different kinds of questions these different explanations serve to answer. The sense in which explanations of adaptations are teleological is spelled out.

Theory and experiment in evolutionary biology

Si les modeles inductiviste et hypothetico-deductiviste sont tous les deux limites dans leur presentation du rapport entre experience et theorie, une combinaison de deux saura peut-etre definir une solution pertinente. Etude du cas de la biologie evolutionniste