Raphael Meldola (1849-1915), an industrial chemist and keen naturalist, under the influence of Darwin, brought new German studies on evolution by natural selection that appeared in the 1870s to the attention of the British scientific community. Meldola's special interest was in mimicry among butterflies; through this he became a prominent neo-Darwinian. His wide-ranging achievements in science led to appointments as president of important professional scientific societies, and of a local club of like-minded amateurs, particularly field naturalists. This is an account (...) of Meldola's early scientific connections and studies related to entomology and natural selection, his contributions to the study of mimicry, and his promotion in the mid-1890s of a more theory driven approach among entomologists. (shrink)

In the life of any species, extinction is the final evolutionary process. It is a common one at present, as the world is entering a major extinction crisis. The pattern of extinction and threat is very non-random, with some taxa being more vulnerable than others. Explaining why some taxa are affected and some escape is a major goal of conservation biology. More ambitiously, a predictive model could, in principle, be built by integrating comparable studies of past and present extinctions. We (...) review progress towards both explanatory and predictive frameworks, comparing correlates of extinction in different groups at different times. Progress towards explanatory models for the current crisis is promising, at least in some well-studied taxa, but the development of a truly predictive model is hampered by the formidable difficulties of integrating studies of present and past extinctions. BioEssays 22:1123–1133, 2000. © 2000 John Wiley & Sons, Inc. (shrink)

Mimicry is often cited as a compelling demonstration of the power of natural selection. By adopting signs of a protected model, mimics usually gain a reproductive advantage by minimising the likelihood of being preyed upon. Yet while natural selection plays a role in the evolution of mimicry, it can be doubted whether it fully explains it. Mimicry is mediated by the emergence of formally analogous patterns between unrelated organisms and by the fact that these patterns are meaningfully perceived as similar. (...) The perception of similarity is always perceiver-dependent. Similarities between for instance colours are psychophysical phenomena, and their existence is conditioned by an intimate interdependence between perceivers and perceptible reality. In this sense, mimicry is by its very nature dualistic. The analogy in form needed to establish a mimicry does not emerge out of the blue. It depends on the ecological context and the morphogenetic potential of a species. In our proposal, we take into account both the developmental generators of formally analogous structures and the perceptual and cognitive processes that lead to the emergence of mimicry. We show that some of the rather controversial and nowadays largely neglected ideas found in non-Anglo-Saxon literature on mimicry deserve closer attention. We suggest that the diversity of mimicry types is due to differences in variational properties of form-generating and perceptual systems among diverse groups of organisms. We also anticipate that processes studied within social psychology and emotion research probably take place, at least in a simplified form, also in non-human animals. Finally, we argue that these meaning-attributive processes underlie the functionality of mimicry. (shrink)

Observing adaptive evolution is difficult. In the fossil record, phenotypic evolution happens much more slowly than in artificial selection experiments or in experimental evolution. Yet measures of selection on phenotypic traits, with high heritabilities, suggest that phenotypic evolution should also be rapid in the wild, and this discrepancy often remains even after accounting for correlations between different traits (i.e. making predictions using the multivariate version of the breeder's equation). Are fitness correlations with quantitative traits adequate measures of selection in the (...) wild? We should instead view fitnesses as average properties of genotypes, while acknowledging that they can be environment‐dependent. Populations will tend to remain at fitness equilibria, once these are attained, and phenotypes will then be stable. Thus, studying the causes of adaptive change at a genotypic rather than phenotypic level may reveal that, typically, it is occurring too slowly to be easily observed. (shrink)

This article analyzes the role, decisive but all-too unknown, played by the American paleontologist and embryologist Edward Drinker Cope in the argumentation, both biological and metaphysical, of Bergson in his Evolution créatrice. As in the cases of Weismann and, negatively, of Haeckel, this role is all the more important that it is less visible in the explicit references. It concerns three questions: that of aging, which is, for Bergson, the mark of the duration on the organism; that of photosynthesis, which (...) is the chemical phenomenon to which all life is suspended; and, above all, that of the difference between life and matter. This difference is seen by Bergson from the standpoint of a science to which Cope gives great importance too, namely the thermodynamics. (shrink)