Evelyn Fox Keller

Initiation of slime mold aggregation viewed as an instability

Abstract The chemotactic interaction of amoebae, as mediated by acrasin, is evidenced in a variety of ways, the most dramatic of which is aggregation. In this paper we present a mathematical formulation of the general interaction, and provide a detailed analysis of the aggregation process. By analogy with many problems in the physical world, aggregation is viewed as a breakdown of stability caused by intrinsic changes in the basic parameters which characterize the system. This point of view provides a description of aggregation which does not require that any cells be distinguished, but rather assumes a homogeneous population.

Model for chemotaxis

Abstract The chemotactic response of unicellular microscopic organisms is viewed as analogous to Brownian motion. Local assessments of chemical concentrations made by individual cells give rise to fluctuations in path. When averaged over many cells, or a long time interval, a macroscopic flux is derived which is proportional to the chemical gradient. By way of illustration, the coefficients appearing in the macroscopic flux equations are calculated for a particular microscopic model.

A feeling for the organism : the life and work of Barbara McClintock

A biography of the Nobel Prize-winning scientist explains her work in genetics and traces her long unheralded career as a research scientist.

Traveling bands of chemotactic bacteria: a theoretical analysis.

Bands of motile Escherichia coli have been observed to travel at constant speed when the bacteria are placed in one end of a capillary tube containing oxygen and an energy source. Such bands are a consequence of a chemotatic mechanism which permits the bacteria to seek an optimal environment: the bacteria avoid low concentrations and move preferentially toward higher concentrations of some critical substrate. In this paper we develop a phenomenological theory of traveling bands starting with partial differential equations which describe the consumption of the critical substrate and the change in bacterial density due to random motion and to chemotaxis. The analysis shows that a band will form only if chemotaxis is sufficiently strong. The predicted band speed is shown to be in satisfactory agreement with observation. The analysis also predicts the shapes of the graphs of bacterial density and substrate concentration in the traveling band and shows how, from these shapes, one can determine a quantitative measure of the relative strength of chemotaxis.

Feminism and Science

Over the past fifteen years, a new dimension to the analysis of science has emerged. Feminist theory, combined with the insights of recent developments in the history, philosophy, and sociology of science, has raised a number of new and important questions about the content, practice, and traditional goals of science. Feminists have pointed to a bias in the choice and definition of problems with which scientists have concerned themselves, and in the actual design and interpretation of experiments, and have argued that modern science evolved out of a conceptual structuring of the world that incorporated particular and historically specific ideologies of gender. The seventeen outstanding articles in this volume reflect the diversity and strengths of feminist contributions to current thinking about science.

Gender and Science

The requirements of ... correctness in practical judgements and objectivity in theoretical knowledge ... belong as it were in their form and their claims to humanity in general, but in their actual historical configuration they are masculine throughout. Supposing that we describe these things, viewed as absolute ideas, by the single word ‘objective’, we then find that in the history of our race the equation objective = masculine is a valid one (George Simmel, quoted by Horney, 1926, p. 200).

The century beyond the gene

In an increasing number of biological laboratories, the focus of research is shifting from sequence data to the functional meaning of that data. No longer content with structural mappings, there is a renewed interest abroad in what the United States Department of Energy calls, ’Bringing Genomes to Life’. For many, this means a movement beyond ’reductionism’ to a ’systems biology’. The question is, what does this mean?

Models of and Models for: Theory and Practice in Contemporary Biology

Two decades of critique have sensitized historians and philosophers of science to the inadequacies of conventional dichotomies between theory and practice, thereby prompting the search for new ways of writing about science that are less beholden than the old ways to the epistemological mores of theoretical physics, and more faithful to the actual practices not only of physics but of all the natural sciences. The need for alternative descriptions seems particularly urgent if one is to understand the place of theory (and, in parallel, the role of modeling) in contemporary molecular biology, a science where, until now, no division between theory and experiment has obtained, and where distinctions between representing and intervening, and more generally, between basic and applied science, are daily becoming more blurred. Indeed, the very division between theory and experiment threatens to slight the extensive and sophisticated theoretical analyses (and even modeling) on which experimental work in contemporary molecular biology so often depends. My aim in this paper is to find a way of talking about theoretical practices in biology that is directly rooted in the mix of conceptual and material work that biologists do. As an example of such theoretical practices, I choose for the focus of my analysis the development of a model for gene regulation out of the experimental work of Eric Davidson and his colleagues at Cal Tech.

The Mind’S Eye

Feminist thought in the 1970’s and 80’s echoes a number of themes familiar from radical thought of the 60’s. One such theme appears in the revolt against the traditional Western hierarchy of the senses. In this view, the emphasis accorded the visual in Western thought is not only symptomatic of the alienation of modern man, but is itself a major factor in the disruption of man’s “natural” relation to the world. The logic1 of Western thought is too rooted in the visual; its failure, it is implied, derives from an unwholesome division of the senses.

A clash of two cultures

Physicists come from a tradition of looking for all-encompassing laws, but is this the best approach to use when probing complex biological systems?