In “The Origin of Species,” Darwin describes a hypothetical example illustrating that large, slowly reproducing mammals such as the elephant can reach very large numbers if population growth is not affected by regulating factors. The elephant example has since been cited in various forms in a wide variety of books, ranging from educational material to encyclopedias. However, Darwin’s text was changed over the six editions of the book, although some errors in the mathematics persisted throughout. In addition, full details of (...) the problem remained hidden in his correspondence with readers of the Origin. As a result, Darwin’s example is very often misinterpreted, misunderstood or presented as if it were a fact. We show that the population growth of Darwin’s elephant population can be modeled by the Leslie matrix method, which we generalize here to males as well. Darwin’s most often cited figure, about 19 million elephants after 750 years is not a typical outcome, actually a very unlikely result under more realistic, although still hypothetical situations. We provide a recursion formula suggesting that Darwin’s original model corresponds to a tribonacci series, a proof showing that sex ratio is constant over all age classes, and a derivation of a generating function of the sequence. (shrink)

It is often claimed that one of Darwin''s chief accomplishments was to provide biology with a non-teleological explanation of adaptation. A number of Darwin''s closest associates, however, and Darwin himself, did not see it that way. In order to assess whether Darwin''s version of evolutionary theory does or does not employ teleological explanation, two of his botanical studies are examined. The result of this examination is that Darwin sees selection explanations of adaptations as teleological explanations. The confusion in the nineteenth (...) century about Darwin''s attitude to teleology is argued to be a result of Darwin''s teleological explanations not conforming to either of the dominant philosophical justifications of teleology at that time. Darwin''s explanatory practices conform well, however, to recent defenses of the teleological character of selection explanations. (shrink)

Darwinism designates a distinctive form of evolutionary explanation for the history and diversity of life on earth. Its original formulation is provided in the first edition of On the Origin of Species in 1859. This entry first formulates ‘Darwin's Darwinism’ in terms of five philosophically distinctive themes: (i) probability and chance, (ii) the nature, power and scope of selection, (iii) adaptation and teleology, (iv) nominalism vs. essentialism about species and (v) the tempo and mode of evolutionary change. Both Darwin and (...) his critics recognized that his approach to evolution was distinctive on each of these topics, and it remains true that, though Darwinism has developed in many ways unforeseen by Darwin, its proponents and critics continue to differentiate it from other approaches in evolutionary biology by focusing on these themes. This point is illustrated in the second half of the entry by looking at current debates in the philosophy of evolutionary biology on these five themes, with a special focus on Stephen Jay Gould's The Structure of Evolutionary Theory. (shrink)

Different accounts of Skinner's work are often in conflict. Some interpretations, for example, regard Skinner as a mechanist. Other interpretations regard Skinner as a selectionist. An alternative interpretation is to see Skinner as employing both views with changes in these views and their proportionate relations over time. To clarify these distinctions, it is helpful to see Skinner's work against the background of similar changes that have been taking place in Western Culture. An extended and overlapping shift in cultural values has (...) occurred from modernism to postmodernism. Some key distinctions in this shift are that modernism emphasizes abstract simplicity, permanent necessity, and absolutely certain sources of truth. Postmodernism emphasizes complex and concrete contexts, probability, and explanations of change in terms of consequences. Skinner shows a similarly extended and overlapping shift over time that results in separate sets of responses which may be regarded as two sides or two selves of Skinner: one an organized collection of responses aligned with modernism, another an organized collection of responses aligned with postmodernism. (shrink)

A number of areas of biology raise questions about what is of value in the natural environment and how we ought to behave towards it: conservation biology, environmental science, and ecology, to name a few. Based on my experience teaching students from these and similar majors, I argue that the field of environmental ethics has much to teach these students. They come to me with pent-up questions and a feeling that more is needed to fully engage in their subjects, and (...) I believe some exposure to environmental ethics can help focus their interests and goals. I identify three primary areas in which environmental ethics can con- tribute to their education. The first is an examination of who (or what) should be considered to be part of our moral community (i.e., the community to whom we owe direct duties). Is it humans only? Or does it include all sentient life? Or all life? Or ecosystems considered holistically? Often, readings implicitly assume one or more of these answers; the goal is to make the student more sensitive to these implicit claims and to get them to think about the different reasons that support them. The second area, related to the first, is the application of the different answers concerning the extent of the ethical community to real environmental issues and problems. Students need to be aware of how the different answers concerning the moral community can imply conflicting answers for how we should act in certain cases and to think about ways to move toward conflict resolution. The third area in which environmental ethics can contribute is a more conceptual one, focusing on central concepts such as biodiversity, sustainability, species, and ecosystems. Exploring and evaluating various meanings of these terms will make students more reflective and thoughtful citizens and biologists, sensitive to the implications that different conceptual choices make. (shrink)