Foundations of Ecology

Classic Papers with Commentaries

Leslie A. Real,James H. Brown

• Editore: University of Chicago Press
• Anno: 2012
• ISBN:
  9780226182100
• Argomento: Biological Sciences
• Categoria: Science General

Assembled here for the first time in one volume are forty classic papers that have laid the foundations of modern ecology. Whether by posing new problems, demonstrating important effects, or stimulating new research, these papers have made substantial contributions to an understanding of ecological processes, and they continue to influence the field today.The papers span nearly nine decades of ecological research, from 1887 on, and are organized in six sections: foundational papers, theoretical advances, synthetic statements, methodological developments, field studies, and ecological experiments. Selections range from Connell's elegant account of experiments with barnacles to Watt's encyclopedic natural history, from a visionary exposition by Grinnell of the concept of niche to a seminal essay by Hutchinson on diversity.Six original essays by contemporary ecologists and a historian of ecology place the selections in context and discuss their continued relevance to current research. This combination of classic papers and fresh commentaries makes Foundations of Ecology both a convenient reference to papers often cited today and an essential guide to the intellectual and conceptual roots of the field.Published with the Ecological Society of America.

PART 1

Foundational Papers

Defining Ecology as a Science

Sharon E. Kingsland

The origins of ecology as a science began with the application of experimental and mathematical methods to the analysis of organism-environment relations, community structure and succession, and population dynamics. The word “oecology” was first coined in the 1860s by a German zoologist, Ernst Haeckel. As a convert to Charles Darwin’s theory of evolution, Haeckel believed that a term was needed to refer to the study of the multifaceted struggle for existence that Darwin had discussed in his 1859 treatise On the Origin of Species (McIntosh 1985, pp. 7–8).

In his book, Darwin had reviewed the diverse meanings of the struggle for existence, a metaphor standing for all the factors that affected the organism’s survival and reproduction. His argument was influenced by his reading of Thomas Robert Malthus’s controversial Essay on Population, first published in 1798, which pointed out that populations would, if left unchecked, tend to increase geometrically and would soon outstrip their food supply. Malthus had asked his readers to consider the consequences of the struggle that would inevitably follow from this population pressure. He concluded that because this population pressure could never be eliminated, we would never be able to create a truly Utopian society where war, famine, and vice were absent. He was advising the Utopian social thinkers of his time to adopt a more realistic and conservative estimate of the potential for human progress.

Darwin read the sixth edition of the Essay on Population (1826) in 1838, soon after returning from a five-year voyage around the world. In England, when he had had time to reflect on the observations he had made, he realized that species had probably originated from preexisting species and had not been specially created by God. Reading Malthus gave him a crucial insight that eventually led to his theory of natural selection. By turning Malthus’s logic back to the natural world, Darwin deduced that the tendency to overproduction would lead to intense competition, heavy mortality, and therefore to an unconscious selection process. Given a long enough period of time one species might split into several new species, each with adaptations shaped by the selective pressures of climate, food supply, predation, and competition. Darwin described his theory as the law of Malthus applied to the natural world, but in fact he had brilliantly reversed Malthus’s conclusions by showing that the struggle for existence was the mechanism for open-ended evolutionary change.

The struggle for existence included all forms of competition, direct and indirect, between organisms. One of the most important arguments in Origin of Species was the emphasis Darwin placed on competition between individuals of the same species as the chief mechanism of evolutionary change. Ernst Mayr (1982) has argued that the reading of Malthus was so important because it made Darwin realize that the struggle for existence mainly occurred within the species, that the members of a population were competing with each other. It was common in natural history writing before Darwin to describe a struggle for existence between different species, for instance between predator and prey. Naturalists accepted the idea that predators would kill off the weak, old, or diseased members of a prey population, in other words, that predation was a form of selection of the unfit. This kind of selection, they thought, actually served to preserve the character of the prey species, because only the deviant individuals were picked off.

But competition within the population could produce real changes, as Darwin recognized. If closely similar individuals were competing intensely for resources, then those with traits that gave them superior competitive ability would eventually replace the inferior and less prolific members of the population. Therefore natural selection was a genuinely creative force, not merely a mechanism for the preservation of the species type. Competition within the species had quite a different significance from competition between species. Recognition of the intensity of competition between closely related forms was also crucial to the understanding of the subtlety of adaptation and the patterns of species’ replacement over a large geographical area.

The work of Darwin and other naturalists of the late-nineteenth century stimulated a more rigorous approach to natural history. In the United States, naturalists such as Stephen Alfred Forbes (1844–1930), Henry Chandler Cowles (1869–1939), and Frederic Edward Clements (1874–1945), all working in the Midwest, began to develop new quantitative methods and theoretical principles that would eventually lay the foundations for a new science called ecology. The term “ecology” was first used in America by a group of professional botanists, who in the 1890s began openly to reject traditional descriptive methods of natural history and concentrated instead on physiological studies of the relationship between organisms and their environment (Cittadino 1980). These botanists were greatly influenced by German and Danish studies in plant geography, themselves an outgrowth of the European Darwinian tradition of research on adaptation and environment. In the creation of the discipline of ecology botanists led the way, but their zoological colleagues followed closely behind and by the 1920s had taken the lead in population studies, which became a major field of research in the 1930s.

The science of ecology, as it was understood both by botanists and zoologists at the turn of the century, signified a dynamic, experimental approach to the study of adaptation, community succession, and population interactions. For botanists in particular, the ecologist was a kind of “outdoor physiologist,” someone who studied adaptation and community evolution in the field using the same rigorous methods that the physiologist employed in the laboratory. These botanists were interested in whether the evolution of species could be controlled experimentally by altering the environment, a goal that had obvious agricultural applications. Most of the early biological surveys and other ecological studies were done in connection with the agricultural experiment stations and land-grant colleges being established by the government in each state at the end of the nineteenth century. In the early-twentieth century, much ecological research on evolution, adaptation, and community succession was funded privately by the Carnegie Institution, which established a Desert Botanical Laboratory near Tucson, Arizona in 1902. In 1904, the Carnegie Institution also opened an experimental station for studies of evolution at Cold Spring Harbor, New York, which became a center of genetics research.

As a high profile and trendy scientific field, ecology attracted many practitioners, but the standards of the new science were not always very rigorous. Hence the complaint voiced by one botanist of the old school, Charles E. Bessey, who bemoaned the popularity of this latest “fad,” which seemed only to distract from serious botanical research (Cittadino 1980, p. 171). But the professional interest in ecology was also serious and the field flourished, despite heavy competition from that other great “fad” of the twentieth century, genetics. The Ecological Society of America held its first organizational meeting at the end of 1914 and was officially constituted in 1915 with 284 charter members (Burgess 1977).

Stephen Forbes, who began his ecological career in Illinois in the 1870s, was greatly influenced by Darwinian biology and by the efforts in America to raise the standards in natural history research by such eminent scientific figures as Louis Agassiz, who in 1859 founded the Museum of Comparative Zoology at Harvard University. Stimulated to pursue ecological work by the research ideals of men such as Agassiz, Darwin, and Thomas Henry Huxley, Forbes undertook detailed analyses of the food relations of insects, birds, and fish within the community, believing that exact information was needed before the value of a species to society could be assessed. The immediate justification for his research was its practical importance: his analyses of food webs were pioneering attempts to give agriculture a scientific basis (Forbes 1880). But Forbes also appreciated the importance of setting his data into the broader theoretical framework of evolutionary biology. The enormous labor involved in ecological research was justified partly by its potential contribution to general questions involving the nature of adaptation, the causes of variation, and the origin and extinction of species.

Forbes accepted Darwin’s argument for evolution by natural selection, but missing from Darwin’s discussion was an explanation of how the struggle for existence produced what seemed to be a well-regulated world where population densities remained fairly stable from year to year. This idea of a balance in nature was commonly accepted by natural historians well before Darwin. Forbes integrated this traditional belief, which harkened back to an earlier teleological view of nature as harmoniously regulated for the benefit of all in accordance with divine wisdom, with the new theoretical writing on evolution. To achieve this integration, he had to go beyond Darwin’s own discussion, which did not really address the problem of how balance was achieved between populations.

The theoretical support for the common sense idea that nature was self-regulating came largely from Darwin’s compatriot Herbert Spencer (1820–1903), a philosopher and evolutionist who coined the phrase which we now associate with Darwinian evolution, “survival of the fittest.” Spencer was trained as an engineer and thought of nature as a moving equilibrium between opposing forces, in this case the forces of population increase and decrease. Spencer believed that there was a necessary adjustment of fertility to mortality, a balance that produced rhythmical population changes about a stable equilibrium value. As evolution progressed, these forces came into perfect balance; Spencer believed that eventually evolution itself would come to a halt (Kingsland 1985; Spencer 1874). Spencer’s analysis of evolution, though based almost entirely on armchair reasoning rather than direct observation, was attractive to his contemporaries partly because it supported the prevalent Victorian belief in a harmonious, progressive world. Let the struggle for existence work itself out unfettered, he thought, and improvement would inevitably result (Kingsland 1988).

Spencer himself was not really a Darwinian evolutionist, though he accepted Darwin’s main argument for natural selection. He believed that a more important mechanism of change was direct, hereditary adaptation to the environment. Adaptive change in direct response to the environment was known as “neo-Lamarckian” evolution, named after the French zoologist Jean-Baptiste Lamarck, who in 1809 proposed a theory of evolution based partly on the idea that characteristics acquired during an organism’s lifetime could become hereditary (Lamarck 1984). In the late-nineteenth century most evolutionists viewed both Darwinian selection theory and the neo-Lamarckian theory of direct adaptation to the environment as complementary mechanisms of evolutionary change...

Indice dei contenuti

• Cover
• Copyright
• Title Page
• Contents
• Preface
• Part One. Foundational Papers: Defining Ecology as a Science
• Part Two. Theoretical Advances: The Role of Theory in the Rise of Modern Ecology
• Part Three. Theses, Antitheses, and Syntheses: Conversational Biology and Ecological Debate
• Part Four. Methodological Advances: New Approaches and Methods in Ecology
• Part Five. Case Studies in Natural Systems: Lessons from Nature: Case Studies in Natural Systems
• Part Six. Experimental Manipulations in Lab and Field Systems: Manipulative Experiments as Tests of Ecological Theory
• List of Contributors