Darwin on woman

In his 1871 book The Descent of Man, Darwin exposed the idea of sexual selection as a major principle of human evolution. His main hypothesis, which was already briefly presented in The Origin of Species, is that there exists, besides “natural selection”, another form of selection, milder in its effect, but no less efficient. This selection is operated by females to mate and reproduce with some partners that are gifted with more qualities than others, and more to their taste. At more evolved stages, sexual selection was exerted by men who became able to choose the women most attractive to their taste. However, Darwin insists, sexual selection in the human species is limited by a certain number of cultural practices. If Darwin's demonstration sometimes carried the prejudices of his times regarding gender differences he was the first who took into account the importance of sexual choices in his view on evolution, and who insisted on the evolutionary role of women at the dawn of humanity. Thus, he opened the space for a rich reflection, which after him was widely developed and discussed in anthropological and gender studies.     

Experimenting with Transmutation: Darwin, the Beagle, and Evolution

Detailed analysis of Darwin’s scientific notes and other writings from the Beagle voyage reveals a focus on endemism and replacement of allied taxa in time and in space that began early in the journey. Though it is impossible to determine exactly when Darwin became a transmutationist, the evidence suggests that he was conversant with the transmutational ideas of Lamarck and others and testing (“experimenting” with) them—before he received a copy of Lyell’s Principles of Geology, vol. 2, in November 1832, in which Lyell describes and disputes Lamarck’s theory. To the two rhea species of Patagonia and the four mockingbird species of the Galapagos, we can now add the living Patagonian cavy (rodent) species, and its extinct putatively related species that Darwin collected at Monte Hermoso (Bahia Blanca) in the Fall of 1832, as a replacement pattern absolutely critical to the development of Darwin’s transmutational thinking. Darwin developed his first transmutational theory by adopting “Brocchi’s analogy” (Rudwick 2008)—i.e. that births and deaths of species are analogous to the births and deaths of individuals. Births and deaths of species, as of individuals, are thus explicable in terms of natural causes. Darwin explored these themes and the replacement of the extinct cavy by the modern species explicitly in his February 1835 essay (Darwin 1835a).

The Gentleman and the Rogue: The Collaboration Between Charles Darwin and Carl Vogt

This paper investigates the relationship between the eminent 19th-century naturalists Charles Darwin and Carl Vogt. On two separate occasions, Vogt asked Darwin for permission to translate some of the latter’s books into German, and in both cases Darwin refused. It has generally been assumed that Darwin turned down Vogt as a translator because of the latter’s reputation as a radical libertine who was extremely outspoken in his defence of scientific materialism and atheism. However, this explanation does not fit the facts, since, on closer investigation, Darwin not only gave serious consideration to engaging Vogt as the German translator of two of his books, albeit ultimately rejecting him, but he also collaborated with Vogt on the French editions of his works. In this paper we argue that this was not because Darwin was unaware of Vogt’s personality and blunt writing style; rather, Darwin seems to have decided that the benefits he would gain from their association would clearly outweigh the risk of offending some of his readers: in working with Vogt, who was not only a knowledgeable scientist but also an avowed adherent of Darwinism, Darwin could be assured of the scientific quality of the translation and of an edition that would not distort his central concepts – both of which were by no means matters of course in 19th-century translations of scientific works.     

Darwin, Herschel, and the role of analogy in Darwin’s origin

In what follows, I consider the role of analogy in the first edition of Darwin’s Origin. I argue that Darwin follows Herschel’s methodology and hence exploits an analogy between artificial and natural selection that allows him generalize selection as a cause of evolutionary change. This argument strategy is not equivalent to an argument from analogy. Reading Darwin’s argument as conforming to Herschel’s two-step methodology of causal analysis followed by generalization allows us to understand the role and placement of Darwin’s discussion of artificial selection in the Origin, without making the mistake of portraying Darwin’s argument for the existence and character of natural selection as an analogical argument.     

The Advantages of Theft over Toil: The Design Inference and Arguing from Ignorance

Intelligent design theorist William Dembski hasproposed an ``explanatory filter' fordistinguishing between events due to chance,lawful regularity or design. We show that ifDembski's filter were adopted as a scientificheuristic, some classical developments inscience would not be rational, and thatDembski's assertion that the filter reliablyidentifies rarefied design requires ignoringthe state of background knowledge. Ifbackground information changes even slightly,the filter's conclusion will vary wildly.Dembski fails to overcome Hume's objections toarguments from design.     

Evolution of ageing since Darwin

In the late 19th century, the evolutionary approach to the problem of ageing was initiated by August Weismann, who argued that natural selection was more important for ageing than any physiological mechanism. In the mid-twentieth century, J. B. S. Haldane, P. B. Medawar and G. C. Williams informally argued that the force of natural selection falls with adult age. In 1966, W. D. Hamilton published formal equations that showed mathematically that two’ forces of natural selection’ do indeed decline with age, though his analysis was not genetically explicit. Brian Charlesworth then developed the required mathematical population genetics for the evolution of ageing in the 1970’s. In the 1980’s, experiments using Drosophila showed that the rate of ageing evolves as predicted by Hamilton’s’ forces of natural selection’. The discovery of the cessation of ageing late in life in the 1990’s was followed by its explanation in terms of evolutionary theory based on Hamilton’s forces. Recently, it has been shown that the cessation of ageing can also be manipulated experimentally using Hamilton’s’ forces of natural selection’. Despite the success of evolutionary research on ageing, mainstream gerontological research has largely ignored both this work and the opportunity that it provides for effective intervention in ageing.     

Adaptations: Using Darwin's Origin to teach biology and writing

Charles Darwin's On the Origin of Species is at once familiar and unfamiliar. Everyone knows that the Origin introduced the world to the idea of evolution by natural selection, but few of us have actually read it. We suggest that it is worth taking the time not only to read what Darwin had to say, but also to use the Origin to teach both biology and writing. It provides scientific lessons in areas beyond evolutionary biology, such as ecology and biogeography. In addition, it provides valuable rhetorical lessons—how to construct an argument, write persuasively, make use of evidence, know your audience, and anticipate counterarguments. We have been using the Origin in various classes for several years, introducing new generations to Darwin, in his own words.     

Why Darwin would have loved evolutionary game theory

Humans have marvelled at the fit of form and function, the way organisms'' traits seem remarkably suited to their lifestyles and ecologies. While natural selection provides the scientific basis for the fit of form and function, Darwin found certain adaptations vexing or particularly intriguing: sex ratios, sexual selection and altruism. The logic behind these adaptations resides in frequency-dependent selection where the value of a given heritable phenotype (i.e. strategy) to an individual depends upon the strategies of others. Game theory is a branch of mathematics that is uniquely suited to solving such puzzles. While game theoretic thinking enters into Darwin''s arguments and those of evolutionists through much of the twentieth century, the tools of evolutionary game theory were not available to Darwin or most evolutionists until the 1970s, and its full scope has only unfolded in the last three decades. As a consequence, game theory is applied and appreciated rather spottily. Game theory not only applies to matrix games and social games, it also applies to speciation, macroevolution and perhaps even to cancer. I assert that life and natural selection are a game, and that game theory is the appropriate logic for framing and understanding adaptations. Its scope can include behaviours within species, state-dependent strategies (such as male, female and so much more), speciation and coevolution, and expands beyond microevolution to macroevolution. Game theory clarifies aspects of ecological and evolutionary stability in ways useful to understanding eco-evolutionary dynamics, niche construction and ecosystem engineering. In short, I would like to think that Darwin would have found game theory uniquely useful for his theory of natural selection. Let us see why this is so.     

Deconstructing Darwin: Evolutionary theory in context

The topic of this paper is external versus internal explanations, first, of the genesis of evolutionary theory and, second, its reception. Victorian England was highly competitive and individualistic. So was the view of society promulgated by Malthus and the theory of evolution set out by Charles Darwin and A.R. Wallace. The fact that Darwin and Wallace independently produced a theory of evolution that was just as competitive and individualistic as the society in which they lived is taken as evidence for the impact that society has on science. The same conclusion is reached with respect to the reception of evolutionary theory. Because Darwins contemporaries lived in such a competitive and individualistic society, they were prone to accept a theory that exhibited these same characteristics. The trouble is that Darwin and Wallace did not live in anything like the same society and did not formulate the same theory. Although the character of Victorian society may have influenced the acceptance of evolutionary theory, it was not the competitive, individualistic theory that Darwin and Wallace set out but a warmer, more comforting theory.     

Michael Ruse's Design for Living

The eminent historian and philosopher ofbiology, Michael Ruse, has writtenseveral books that explore the relationship ofevolutionary theory to its larger scientificand cultural setting. Among the questions hehas investigated are: Is evolution progressive? What is its epistemologicalstatus? Most recently, in Darwin and Design:Does Evolution have a Purpose?,Ruse has provided a history of the concept ofteleology in biological thinking, especially inevolutionary theorizing. In his book, he moves quickly from Plato and Aristotle to Kantand such British thinkers as Paley andWhewell. His main focus, though, is on Darwin'stheory and its subsequent fate. Ruserests his history on some shaky historical andphilosophic assumptions, particularly theunexamined notion that evolutionary theory isan abstract entity that isunproblematically realized in differenthistorical periods. He also assumes that Darwinconceived nature as if it were a Manchesterspinning loom – a clanking, dispassionatemachine. A more subtle analysis, which Ruseeschews, might discover that Darwin'sconception of nature owed a strong debt toGerman Romanticism and that he contrivedto infuse nature with moral and aestheticvalues, not to suck them from nature. Ruseproves he is a thinker to contend with, and this essayis quite contentious.     

Natural selection then and now

One often reads the following claims: (1) The modern conception of natural selection differs from Darwin's own conception only with respect to incidental features; (2) Natural selection is a very simple idea with enormous explanatory power. Both claims are problematic. R.A. Fisher famously argued that given a particulate view of inheritance, selection could proceed in a powerful manner even with frequent crossing, small fitness advantages and a low mutation rate. This is quite different from Darwin's view, which (roughly translated into a modern idiom) insists on infrequent crossing, large fitness advantages and a high mutation rate. The modern conception of natural selection is not the same as Darwin's, unless we describe natural selection in the most abstract manner. When so described, the ability of natural selection to account for adaptation is questionable.     

Darwin's puzzling Expression

Charles Darwin's The Expression of the Emotions in Man and Animals (1872) is a very different kind of work from On the Origin of Species (1859). This “otherness” is most extreme in the character of the explanations that Darwin offers in the Expression. Far from promoting his theory of natural selection, the Expression barely mentions that theory, instead drawing on explanatory principles which recall less Darwinian than Lamarckian and structuralist biological theorizing. Over the years, historians have offered a range of solutions to the puzzle of why the Expression is so “non-Darwinian”. Close examination shows that none of these meets the case. However, recent research on Darwin's lifelong engagement with the controversies in his day over the unity of the human races makes possible a promising new solution. For Darwin, emotional expression served the cause of defending human unity precisely to the extent that natural selection theory did not apply.     

Habitat selection within species ofDrosophila: a review of experimental findings

Summary Habitat selection whereby individuals within a population have different microhabitat preferences is possibly important for genetic diversity and stability. It has received a good deal of attention, especially forDrosophila populations. The literature is summarized and an attempt is made to reconcile what appear to be contradictory findings. Some generalizations are drawn: (1) individualDrosophila choose habitats in consistent and characteristic ways; (2) some microhabitat differences are more important to flies than others; (3) genetic factors influence habitat preferences; (4) experiential factors influence habitat preferences; (5) differences in processing ability moderate the influence of experience on habitat choice. It is argued that the traditional analysis of variance models are frequently not very helpful for visualizing the process, and a computational model is suggested instead.     

Why do Foraging Stream Salmonids Move During Summer?

We hypothesize that foraging stream salmonids move during summer because (1) they monitor habitat conditions at a reach scale (100s of m), and (2) dominant fish move when conditions in their present foraging location become sub-optimal relative to conditions at other locations in the reach. To test these ideas, we quantified temporal variation in foraging habitat quality between late spring and early fall in a reach of a small Rocky Mountain brook charr, Salvelinus fontinalis, stream, predicted optimal-foraging fish distributions within the reach, and experimentally manipulated access to foraging sites and measured fish responses. Our results show that high-quality foraging sites were located at certain places in the reach during one period, but at different places during others, consistent with the hypothesis that fish movement is required if dominant fish are to occupy high-quality foraging sites throughout summer. The optimal foraging model was able to predict foraging locations within study pools, but not the exact location of individual fish within the pools or the reach. However, empirical evidence suggests that fish were distributed in order to maximize energy intake at the reach scale. Finally, dominant fish excluded from their preferred foraging location either left the pools (three of six cases), or began to occupy focal points of the next largest fish which, in turn, exited the pool (two of six cases). If habitat selection was occurring only within habitat units, then large fish, when excluded from their preferred locations, would select the next best locations within the pool. Taken together, these results suggest that charr use summertime movements to both monitor habitat conditions at a large spatial scale, and to gain access to optimal foraging locations even as conditions change temporally.     

Morphological defects in cotton hairs and the nature of their origin

In vivo observations of the origin of native defects in cotton hairs were carried out during their development in unopened cotton bolls. It is shown that the formation of these structural defects is related to features of their packing inside the cotton bolts during the formation of the boll segments. A mechanism explaining the origination of these morphological defects is proposed. It is based on the hydrodynamic properties of the cytoplasm at the sites of bending in developing cotton hairs.