The publication of Darwin's On the Origin of Species in 1859 ignited a public storm he neither wanted nor enjoyed. Having offered his book as a contribution to science, Darwin discovered to his dismay that it was received as an affront by many scientists and as a sacrilege by clergy and Christian citizens. To answer the criticism that his theory was a theory only, and a wild one at that, he published two volumes in 1868 to demonstrate that evolution was (...) obvious to anyone who cared to look at a bull in a pasture or a dog on a hearth. In response to those who insisted that species were distinct since creation, Darwin pointed to breeders of pigs and pigeons. In reply to those who protested that human intervention is one thing and natural selection another, he argued, "If organic beings had not possessed an inherent tendency to vary, man could have done nothing." To counter those who scorned his descriptions of species in exotic places, he submitted local evidence of cabbages and cauliflower. Based on a wide array of sources, from ancient pictographs to Polish roosters, from skins and from skeletons, from scientific journals and breeding manuals, Darwin assembled a mass of proof--and a hypothesis about species reversion that risked his reputation anew. The Variation of Animals and Plants under Domestication is a two-volume compilation of his thorough and intensive research and the revolutionary conclusions that resulted. The first portion of his work is dedicated to a meticulous analysis of various aspects of plant and animal life, including an inventory of varieties and their physical and behavioral characteristics, investigation of the impact of a species' surrounding environment and the role that both natural and forced changes in this environment have had. Darwin then turns to a richly detailed discussion of the roles of inheritance and crossing in the development of species. A wealth of illustrations further support and enhance his findings. This fascinating, invaluable, and courageous undertaking eventually formed the foundation for our current understanding of evolution. "In science as in politics the victors tend to write the history books. As a result, the record of the past is edited, intentionally or unintentionally, so that it focuses mainly on the precursors of contemporary orthodoxy. Such a focus may accurately represent the genealogy of modern ideas, but it almost inevitably misrepresents the historical experience of their progenitors... Even the powerful, persuasive, and ultimately triumphant theory of evolution by natural selection required not only defense, but repeated buttressing and revision. Variation showed Darwin hard at work on this rearguard action, using the materials he had at hand... His information was gleaned from the observations of fanciers, breeders, and amateur naturalists, as well as from the treatises of those on the cutting edge of zoology and botany. As hindsight narrows the historical spotlight, it imposes its own sense of hierarchy on the preoccupations of the past. But Darwin was interested in all of these topics, valued all of these sources, and belonged, to a greater or lesser extent, to all of these communities."--from the Introduction. (shrink)

In the early nineteenth century, a group of German biologists led by Johann Friedrich Blumenbach and Karl Friedrich Kielmeyer initiated a search for laws of biological organization that would explain the phenomena of form and function and establish foundations for a unified theory of life. The tradition spawned by these efforts found its most important spokesman in Karl Ernst von Baer. Timothy Lenoir chronicles the hitherto unexplored achievements of the practitioners of this research tradition as they aimed to place functional (...) morphology at the heart of a new science, which they called "biology." Strongly influenced by Immanuel Kant, the biologists’ approach combined a sophisticated teleology with mechanistic theories and sparked bitter controversies with the rival programs, mechanistic reductionism and Darwinism. Although temporarily eclipsed by these two approaches, the morphological tradition, Lenoir argues, was not vanquished in the field of scientific debate. It contributed to pathbreaking research in areas such as comparative anatomy, embryology, paleontology, and biogeography. Preface Introduction 1. Vital Materialism 2. The Concrete Formulation of the Program: From Vital Materialism to Developmental Morphology 3. Teleomechanism and the Cell Theory 4. The Functional Morphologists 5. Worlds in Collision 6. Teleomechanism and Darwin’s Theory Epilogue Notes Name Index Index. (shrink)

Many biologists assume, as Darwin did, that natural selection acts mainly on late embryonic or postnatal development. This view is consistent with von Baer's observations of morphological divergence at late stages. It is also suggested by the conserved morphology and common molecular genetic mechanisms of pattern formation seen in embryos. I argue here, however, that differences in adult morphology may be generated at a variety of stages. Natural selection may have a major action on developmental mechanisms during the organogenetic period, (...) because this is when many adult traits are specified. Evolutionary changes in these early developmental mechanisms probably include subtle shifts in the timing of gene expression. Changes of this kind have little or no gross effect on the anatomy of the embryo; they are only phenotypically expressed, or readily detected, when amplified at later stages. The phylotypic stage, the developmental hourglass, modularity, and von Baerian divergence are reassessed in terms of these arguments. BioEssays 21:604–613, 1999. © 1999 John Wiley & Sons, Inc. (shrink)

This textbook is aimed at newcomers to nonlinear dynamics and chaos, especially students taking a first course in the subject. The presentation stresses analytical methods, concrete examples and geometric intuition. The theory is developed systematically, starting with first-order differential equations and their bifurcations, followed by phase plane analysis, limit cycles and their bifurcations, and culminating with the Lorenz equations, chaos, iterated maps, period doubling, renormalization, fractals, and strange attractors.A unique feature of the book is its emphasis on applications. These include (...) mechanical vibrations, lasers, biological rhythms, superconducting circuits, insect outbreaks, chemical oscillators, genetic control systems, chaotic waterwheels, and even a technique for using chaos to send secret messages. In each case, the scientific background is explained at an elementary level and closely integrated with the mathematical theory.Richly illustrated, and with many exercises and worked examples, this book is ideal for an introductory course at the junior/senior or first-year graduate level. It is also ideal for the scientist who has not had formal instruction in nonlinear dynamics, but who now desires to begin informal study. The prerequisites are multivariable calculus and introductory physics. (shrink)

In 1972, we proposed a theory of biological pattern formation in which concentration maxima of pattern forming substances are generated through local self- enhancement in conjunction with long range inhibition. Since then, much evidence in various developmental systems has confirmed the importance of autocatalytic feedback loops combined with inhibitory interaction. Examples are found in the formation of embryonal organizing regions, in segmentation, in the polarization of individual cells, and in gene activation. By computer simulations, we have shown that the theory (...) accounts for much of the regulatory phenomena observed, including signalling to regenerate removed parts. These self- regulatory features contribute to making development robust and error-tolerant. Furthermore, the resulting pattern is, to a large extent, independent of the details provided by initial conditions and inducing signals. (shrink)

Historically, philosophers of biology have tended to sidestep the problem of development by focusing primarily on evolutionary biology and, more recently, on molecular biology and genetics. Quite often too, development has been misunderstood as simply, or even primarily, a matter of gene activation and regulation. Nowadays a growing number of philosophers of science are focusing their analyses on the complexities of development, and in Embryology, Epigenesis and Evolution Jason Scott Robert explores the nature of development against current trends in biological (...) theory and practice and looks at the interrelations between development and evolution, an area of resurgent biological interest. Clearly written, this book should be of interest to students and professionals in the philosophy of science and the philosophy of biology. (shrink)

Problems and Paradigms is a feature series devoted to discussions of major problems in biology. Past contributions have dealt with the selector gene hypothesis, problems of pattern formation, the phenomenon of paramutation, theories of aging, and the origins of life. In this article, Brian C. Goodwin discusses the problem of morphogenesis, in terms of the idea of the genetic program and in the light of recent findings.

In describing the flawless regularity of developmental processes and the correlation between changes at certain genetic loci and changes in morphology, biologists frequently employ two metaphors: that genes ‘control’ development, and that genomes embody ‘programs’ for development. Although these metaphors have an admirable sharpness and punch, they lead, when taken literally, to highly distorted pictures of developmental processes. A more balanced, and useful, view of the role of genes in development is that they act as suppliers of the material needs (...) of development and, in some instances, as context‐dependent catalysts of cellular changes, rather than as ‘controllers’ of developmental progress and direction. The consequences of adopting this alternative view of development are discussed. (shrink)