According to sources both in print and at a recent meeting, evolutionary theory is currently undergoing change which some would characterize as a New Synthesis, and others as an Extended Synthesis. This article argues that the important changes involve recognizing that there are three means by which evolutionary change can be initiated and three corresponding modes of evolutionary drift. It compares the three and goes on to discuss the scale of innovation and extended or inclusive and Lamarckian inheritance. It concludes (...) from these that “new trends in evolutionary biology” are in part a new, and in part an extended evolutionary synthesis. (shrink)

Despite a revived interest in explaining the evolution of anisogamy in recent years (i.e. different—micro and macrogametes), there remain more questions than answers. The topic is important because it is thought to be the foundation of the theory of gender differences and relations. Twelve of these questions are briefly reviewed here—(1) the distinction between sex and sexual types; (2) the distinction between mating types and anisogamy; (3) the possible role of ecological as well as social evolution in proto-gender differences and (...) relations; (4) the life history strategies involved; (5) whether the relevant social relationships are based on conflict or cooperation; (6) the origin and properties of meiosis; (7) the conformity of theories with sex allocation theory; (8) the relevance of multiple levels of selection; (9) appropriate modelling strategies; (10) the relationship between the kind of gametes produced and secondary sexual characteristics; (11) the relevance to humans; and (12) how realistic the search for a single explanation is. It is concluded that polarized sexuality may be a form of trade. (shrink)

The Modern Synthesis (MS) is the current paradigm in evolutionary biology. It was actually built by expanding on the conceptual foundations laid out by its predecessors, Darwinism and neo-Darwinism. For sometime now there has been talk of a new Extended Evolutionary Synthesis (EES), and this article begins to outline why we may need such an extension, and how it may come about. As philosopher Karl Popper has noticed, the current evolutionary theory is a theory of genes, and we still lack (...) a theory of forms. The field began, in fact, as a theory of forms in Darwin’s days, and the major goal that an EES will aim for is a unification of our theories of genes and of forms. This may be achieved through an organic grafting of novel concepts onto the foundational structure of the MS, particularly evolvability, phenotypic plasticity, epigenetic inheritance, complexity theory, and the theory of evolution in highly dimensional adaptive landscapes. (shrink)

In the six decades since the publication of Julian Huxley's Evolution: The Modern Synthesis, spectacular empirical advances in the biological sciences have been accompanied by equally significant developments within the core theoretical framework of the discipline. As a result, evolutionary theory today includes concepts and even entire new fields that were not part of the foundational structure of the Modern Synthesis. In this volume, sixteen leading evolutionary biologists and philosophers of science survey the conceptual changes that have emerged since Huxley's (...) landmark publication, not only in such traditional domains of evolutionary biology as quantitative genetics and paleontology but also in such new fields of research as genomics and EvoDevo. Most of the contributors to Evolution—The Extended Synthesis accept many of the tenets of the classical framework but want to relax some of its assumptions and introduce significant conceptual augmentations of the basic Modern Synthesis structure—just as the architects of the Modern Synthesis themselves expanded and modulated previous versions of Darwinism. This continuing revision of a theoretical edifice the foundations of which were laid in the middle of the nineteenth century—the reexamination of old ideas, proposals of new ones, and the synthesis of the most suitable—shows us how science works, and how scientists have painstakingly built a solid set of explanations for what Darwin called the "grandeur" of life. (shrink)

Interest in the most general theory of the evolutionary ecology of life histories ever proposed—that of density-independent versus density-dependent selection—peaked in the 1980s and 1990s respectively but declined somewhat thereafter because of arguments over its theoretical coherence and some empirical failures; although as is shown here, not so much as is commonly supposed. In this article, some conceptual analyses and clarification of terms in the conditions for its application, and in the explanantia of the theory are presented. These make intelligible (...) plausible mechanisms linking the explanantia and the explananda of the theory that are both theoretically coherent and clarify what predictions it does not and does make including about senescence. (shrink)