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Theories of density-dependent natural selection state that at extreme population densities evolution produces alternative life histories due to trade-offs. The trade-offs are presumed to arise because those genotypes with highest fitness at high population densities will not also have high fitness at low density and vice-versa. These predictions were tested(More)
There is presently a conflict between fossil- and molecular-based evolutionary time scales. Molecular approaches for dating the branches of the tree of life frequently lead to substantially deeper times of divergence than those inferred by paleontologists. The discrepancy between molecular and fossil estimates persists despite the booming growth of sequence(More)
1 Theodosius Dobzhansky (1900-1975) was one of the principal architects of the so-called synthetic theory of evolution. 2 Born and initially trained in Russia, where he became an entomologist and zoologist with wide-ranging interests, he brought a rich background in systematics and study of natural populations with him when he came to the United States to(More)
The capacity to appreciate beauty is one of our species' most remarkable traits. Although knowledge about its neural correlates is growing, little is known about any gender-related differences. We have explored possible differences between men and women's neural correlates of aesthetic preference. We have used magnetoencephalography to record the brain(More)
7.1 Introduction Two kinds of factors set the tempo and direction of organic and cultural evolution, those external to biotic evolutionary process, such as changes in the earth's physical and chemical environments, and those internal to it, such as the time required for chance factors to lead lineages across adaptive valleys to a new niche space (Valentine(More)
Articles E cological communities comprise complex networks of individuals interacting with each other and with their environment. Two major challenges for scientists, managers, and policymakers are (1) understanding the forces that organize these heterogeneous systems across space and time (Levin 1992, Levin et al. 1997, Brown et al. 2002) and (2) using(More)
With the publication in 1859 of On the Origin of Species by Means of Natural Selection, Charles Darwin established that evolution by common descent was the dominant scientific explanation for nature's diversity. This was to be his greatest gift to science and society. Scientists agree that the evolutionary origin of animals and plants is a scientific(More)
Despite the prominence of the Azteca-Cecropia interaction as the focus of extensive ecological investigation, a reliable phylogeny of the Azteca ants has been lacking, primarily because many of the morphological and behavioral characters are phylogenetically uninformative or conflicting. A phylogenetic analysis of a select set of Azteca ants, including six(More)