Niche Construction

Niche construction is a concept that originated in evolutionary biology. It challenges the assumption that ecological niches are empty, pre-existing environmental spaces into which passive organisms must be fitted through adaptive natural selection. Niche construction theory argues that organisms construct their own niches when they actively select features of their current environment on which to rely, thereby influencing the selection pressures they encounter. Niche construction was developed after 1975, during a period when sociobiology had gained popularity among evolutionary theorists, with claims that all features of organisms, from anatomy to social behavior, could be explained in terms of natural selection on genes. Organisms, indeed, were disappearing as agents in evolutionary narratives. By the mid-1980s, however, sociobiological narratives were facing challenges. Perhaps the most successful were mounted by evolutionary theorists who borrowed mathematical models from population biology and used them to explore how Darwinian selection might operate on units of culture as well as on genes. During this period, the original writings on niche construction were also re-examined, and ways were sought to model the process mathematically. These efforts led to the publication in 2003 of the landmark text Niche Construction: The Neglected Process in Evolution, by John Odling-Smee, Kevin Laland, and Marcus Feldman. This volume has since become widely influential, not only among theorists of biological and cultural evolution but also among scholars in fields such as ecology and developmental biology, as well as in the human sciences. In anthropology, archaeologists and biological anthropologists in particular have found niche construction theoretically helpful for explaining such phenomena as our ancestors’ ability to outlast other hominin species in the Pleistocene, our success in domesticating plants and animals after ten thousand years ago, and our dramatic remaking of global landscapes and species distributions in what has been called the Anthropocene. As a result, work on niche construction is coming to intersect in provocative ways across the subfields of anthropology with work by sociocultural anthropologists interested in areas such as environmental anthropology, material culture, and multispecies ethnography.

The incubatory chamber of marsupial carditids (Bivalvia: Carditidae: Thecaliinae) as an exaptation

Marsupial carditids of the subfamily Thecaliinae are characterized by the presence of an “incubatory chamber” in female shells, where the eggs hatch and develop during their first stages. According to recent phylogenetic studies, Thecaliinae are closely related to Carditinae, a group that has a byssal gape. This structure occurs in the same area as the incubatory chamber, and both structures could be evolutionarily related. Using the newest phylogenetic context for the subfamilies, we test whether the incubatory chamber of Thecaliinae is related to characters present in Carditinae. We also provided a more precise definition of the implied structures. Two distinct morphologies for the incubatory chamber are described: one with an exteriorly opened pouch (present in the genera Powellina and Milneria) and the other with a completely internal funicular infold (present in Thecalia). The byssal gape is present in the Cardiobyssata clade (Carditamerinae + (Carditinae + Thecaliinae)), and we discuss whether the incubatory chamber could be the result of an exaptation event, and the possible evolutionary pathways implied. According to the present evidence, we propose a co-optation of the byssal gape into a new function (brooding of larvae) at some point during the transition from the Carditinae to the Thecaliinae lineages, thus determining an exaptation. Adaptative processes probably modified this structure into the incubatory chamber (an external pouch first, and a funicular infold later). We discuss alternative scenarios and implications on phylogenetic studies and the importance of considering non-adaptative evolutionary scenarios in the study of evolutionary narratives.

Rethinking megafauna

Concern for megafauna is increasing among scientists and non-scientists. Many studies have emphasized that megafauna play prominent ecological roles and provide important ecosystem services to humanity. But, what precisely are ‘megafauna’? Here, we critically assess the concept of megafauna and propose a goal-oriented framework for megafaunal research. First, we review definitions of megafauna and analyse associated terminology in the scientific literature. Second, we conduct a survey among ecologists and palaeontologists to assess the species traits used to identify and define megafauna. Our review indicates that definitions are highly dependent on the study ecosystem and research question, and primarily rely on ad hoc size-related criteria. Our survey suggests that body size is crucial, but not necessarily sufficient, for addressing the different applications of the term megafauna. Thus, after discussing the pros and cons of existing definitions, we propose an additional approach by defining two function-oriented megafaunal concepts: ‘keystone megafauna’ and ‘functional megafauna’, with its variant ‘apex megafauna’. Assessing megafauna from a functional perspective could challenge the perception that there may not be a unifying definition of megafauna that can be applied to all eco-evolutionary narratives. In addition, using functional definitions of megafauna could be especially conducive to cross-disciplinary understanding and cooperation, improvement of conservation policy and practice, and strengthening of public perception. As megafaunal research advances, we encourage scientists to unambiguously define how they use the term ‘megafauna’ and to present the logic underpinning their definition.

From Islands to Archipelagos

The texts examined in Chapter 4 explore islands in geo(morpho)logical space-time. The chapter begins by discussing how the relational poetics of Darwin’s and Wallace’s writings ask readers to reimagine planetary space as a discontinuous multiplicity of shifting islands. The notion of a geopoetic resonance between the material energies of the physical world and the poetic energies of language guides the analyses of three literary responses to Darwin, Wallace, and their successors. H. G. Wells’s The Island of Doctor Moreau (1896) and ‘Aepyornis Island’ (1894) figure islands as beleaguered territories haunted by the spectre of human extinction. However, their geopoetic descriptions of volcanism and coral suspend these evolutionary narratives. A century later, Amitav Ghosh’s The Hungry Tide explores the radical poetic implications of Darwin and Wallace’s archipelagic thinking. In the novel, the human element intersects with other living forms, physical geography, and textual spaces to form a mutable landscape shaped by conflicts.

Re-examining Darwin and Human Evolution from a Partnership Perspective: A Conversation with David Loye

Riane Eisler talks with her husband, social psychologist and Darwin scholar David Loye, about his re-examination of Darwin’s theory of evolution and how and why the role of love, moral sensitivity, mutual aid, and other partnership values has been ignored in most evolutionary narratives, whereas selfishness, violence, and other traits key to imposing and maintaining domination systems have been presented as key to human evolution.