Introduction to the Ecology Section

Transcription

1 Introduction to the Ecology Section Gregory M. Mikkelson Department of Philosophy and School of Environment McGill University, 855 Sherbrooke Street West Montréal, Québec H3A 2T7 CANADA In: Skipper, R. A. Jr., C. Allen, R. Ankeny, C. F. Craver, L. Darden, G. M. Mikkelson, and R. C. Richardson, editors. Philosophy across the Life Sciences. MIT. Cambridge, MA. Ecology is the science of who eats whom, of what lives where and when it got there, of why the world is green, and how the human species might fit in. Despite, or perhaps because of, the fascinating variety of its subject matter, ecology has received less attention from philosophers of biology than have other fields notably genetics and evolutionary biology. Our time of catastrophic environmental change calls for dramatic improvements in ecological understanding. It thus behooves philosophers along with everybody else to become more familiar with ecological science. Ecology deals with several levels of organization in nature. Traditionally, it has focused on single-species populations, multi-species communities, and ecosystems. But individual organisms, as well as landscapes comprising many populations, communities, or ecosystems, have also received a great deal of attention. Many of the philosophical issues arising from ecology concern the relationships between these different levels of organization. Others concern the relationships between ecology and other sciences, such as economics. But perhaps most important are questions about the relationships between 1

2 ecological science and environmental ethics. This section of this book will focus on the first and third of these kinds of issue. For discussions of the second kind, see delaplante (2004) and Mikkelson (2007). Community and population ecology The first reading in this section samples some of the themes that ecology has focused on over the years, and some of the key figures who have shaped the field. This piece is excerpted from a recent book arguing for the importance of ecological drift change in the relative abundances of different species, that is independent of any overall competitive advantage of some species over others (cf. Mikkelson 2005). Hubbell (2001) argues that ecological drift plays a role in multi-species communities that is comparable in importance to the role played by genetic drift within single-species populations. In the section reprinted below, he cites the theory of island biogeography as an inspiration for his own theory. The theory of island biogeography was developed in the 1960's, and is widely acknowledged to have been a crucial development in the history of ecology. Hubbell also touches on early-20 th -Century debates about the degree to which communities resemble organisms vs. random collections of species populations (cf. Odenbaugh 2006, Eliot 2007). Similar debates became especially strident during the 1970's and 1980's. Some population ecologists asserted that not only do communities bear no resemblance to organisms, but they may not be interesting or important levels of organization at all. Callicott (1996 and below) deftly rebuts "deconstructive ecology" of this type, by delving into the metaphorical origins of the community concept. Callicott also sketches the history, up to 1996, of the idea that communities with more species tend to be more stable. This hypothesis took a beating during the 2

3 deconstructive phase of ecology, but has become firmly re-established as the concept of stability and the methods for investigating it have improved (Mikkelson 2008). Finally, Callicott takes gene-centric sociobiologists to task for committing the fallacy of composition, in their assumption that if our genes are selfish, then we must be too. To commit the fallacy of composition is to make an invalid inference that just because the parts of some object have a certain property, the whole object must have that same property as well. Ecosystem and physiological ecology Other philosophers have embraced deconstructive ecology, rather than attempting to refute it as Callicott has. One of these is Mark Sagoff, who has taken aim at ecosystem, rather than community, ecology. An ecosystem is, according to one standard definition, a community of organisms plus the matter and energy with which they interact. But alternative definitions exist. In the third reading below, delaplante and Odenbaugh point out that such multiplicity in the definitions of key terms is widespread in science. And rather than being a problem, such variety at least sometimes indicates an active, successful research program. delaplante and Odenbaugh criticize Sagoff for assuming otherwise, as well as for several other unwarranted presuppositions of his critique of ecosystem ecology. As delaplante and Odenbaugh point out, deconstructive ecologists often seek to justify their claims by invoking reductionism the idea that wholes should be explained primarily in terms of their parts, rather than in terms of their environments, or in terms of the larger wholes in which they are embedded. In the fourth reading below, I argue for the alternative position what different authors have called a "dialectical", "systemist", or 3

4 "holistic" approach. According to the latter, when it comes to predicting, explaining and/or controlling certain properties of communities or ecosystems as a whole, other community or ecosystem properties, and/or the properties of the surrounding environments or landscapes in which they are embedded, are just as important as population and organismal properties. After rehearsing four general arguments against reductionism in ecology, I analyze the particular case of recent work on a "metabolic theory of ecology". Ecological facts and values At the end of my contribution, I draw an analogy between reductionistic vs. holistic approaches within ecological science and environmental ethics. Earlier, we saw that Callicott's commentary is motivated by concern about the implications of science for ethics. In the fifth and final reading, Norton (1998 and below) argues for an additional kind of connection between the two. He urges scientists to increase their use of valueladen terms such as "health", "integrity", and their opposites for describing and explaining ecological systems. Economists use such loaded terminology e.g., "efficiency", "welfare", etc. all the time. According to Norton, this partly explains the sway held by economists over environmental law and policy, whereas ecologists' shyness about using such terms has compromised the ability of citizens and politicians to grasp the true nature and extent of environmental problems and solutions. Norton's thesis raises some fundamental issues. For example, it flies in the face of the common view that science and ethics are radically distinct. According to this view, science is the province of objective facts, and ethics the realm of subjective values. Norton disavows this "myth", and associates it with logical positivism a school of 4

5 thought long discredited within philosophy. However, Norton like many other prominent environmental ethicists, including Callicott has resisted a leading alternative to the positivist view: objective moral realism. Given that this latter position has attracted increasing attention and support, perhaps the time has come to breathe new meaning into the old notion of a "moral science", and to give it wider scope, encompassing at least part of the natural world, as well as the human sphere (cf. Kelly 2003, Oddie 2006). Acknowledgments Thanks to Kevin delaplante and Jay Odenbaugh for helpful feedback on this introduction. References Callicott, J. B Do deconstructive ecology and sociobiology undermine Leopold's land ethic? Environmental Ethics 18: delaplante, K Toward a more expansive conception of ecological science. Biology and Philosophy 19: Eliot, C Method and metaphysics in Clements' and Gleason's ecological explanations. Studies in History of Biological and Biomedical Sciences 38: Hubbell, S. P The Unified Neutral Theory of Biodiversity and Biogeography. Princeton University. Princeton, NJ. Kelly, C A Theory of the Good. Ph.D. dissertation, University of Colorado. Boulder, CO. Mikkelson, G. M Niche-based vs. neutral models of ecological communities. Biology and Philosophy 20:

6 Mikkelson, G. M Ecological economics. In: Ruse, M., editor. Philosophy of Biology. Prometheus Books. Amherst, NY. Pp Mikkelson, G. M Diversity-stability hypothesis. In: Callicott, J. B., R. Frodeman, V. Davion, B. G. Norton, C. Palmer, and P. B. Thompson, editors. Encyclopedia of Environmental Ethics and Philosophy. MacMillan. Farmington Hills, MI. Norton, B. G Improving ecological communication: The role of ecologists in environmental policy formation. Ecological Applications 8: Oddie, G Value, Reality, and Desire. Oxford University. New York, NY. Odenbaugh, J Ecology. In: Sarkar, S. and J. Pfeifer, editors. The Philosophy of Science: An Encyclopedia. Routledge. New York, NY. Pp