Geophagy is the intentional consumption of earth. Although widely documented among vulnerable populations, including children and pregnant women, the causes and consequences of geophagy remain poorly understood. Relevant literature was, therefore, reviewed to describe geophagy across species, geographies, life stages, and disease states. After a brief consideration of hypothesized etiologies, the potential harmful and beneficial consequences of geophagy are described, considering current evidence for each. Data available to date suggest that the greatest potential risks of geophagy include toxicity or heavy metal poisoning, and diseases resulting from consumed clays binding nutrients and beneficial pharmaceuticals in the gut. Evidence also suggests that geophagy may be beneficial by protecting against harmful pathogens and toxins through two distinct physiological pathways. Future research should explore causal relationships between geophagy and iron deficiency, as well as investigate the biological and psychosocial conditions that govern geophagy.

Predicting whether a species is likely to go extinct (or not) is one of the fundamental objectives of conservation biology, and extinction risk classifications have become an essential tool for conservation policy, planning and research. This sort of prediction is feasible because the extinction processes follow a familiar pattern of population decline, range collapse and fragmentation, and, finally, extirpation of sub-populations through a combination of genetic, demographic and environmental stochasticity. Though less well understood and rarely quantified, the way in which science and society respond to population decline, extirpation and species extinction can also have a profound influence, either negative or positive, on whether a species goes extinct. For example, species that are highly sought after by collectors and hobbyists can become more desirable and valuable as they become rarer, leading to increased demand and greater incentives for illegal trade – known as the anthropogenic Allee effect. Conversely, species that are strongly linked to cultural identity are more likely to benefit from sustainable management, high public support for conservation actions and fund-raising, and, by extension, may be partially safeguarded from extinction. More generally, human responses to impending extinctions are extremely complex, are highly dependent on cultural and socioeconomic context, and have typically been far less studied than the ecological and genetic aspects of extinction. Here, we identify and discuss biocultural aspects of extinction and outline how recent advances in our ability to measure and monitor cultural trends with big data are, despite their intrinsic limitations and biases, providing new opportunities for incorporating biocultural factors into extinction risk assessment.

Evolutionary perspectives on menopause have focused on explaining why early reproductive cessation in females has emerged and why it is rare throughout the animal kingdom, but less attention has been given to exploring patterns of diversity in age at natural menopause. In this paper, we aim to generate new hypotheses for understanding human patterns of diversity in this trait, defined as age at final menstrual period. To do so, we develop a multilevel, interdisciplinary framework, combining proximate, physiological understandings of ovarian ageing with ultimate, evolutionary perspectives on ageing. We begin by reviewing known patterns of diversity in age at natural menopause in humans, and highlight issues in how menopause is currently defined and measured. Second, we consider together ultimate explanations of menopause timing and proximate understandings of ovarian ageing. We find that ovarian ageing is highly constrained by ageing of the follicle – the somatic structure containing the oocyte – suggesting that menopause timing might be best understood as a by-product of ageing rather than a facultative adaptation. Third, we investigate whether the determinants of somatic senescence also underpin menopause timing. We show that diversity in age at menopause can be, at least partly, explained by the genetic, ecological and life-history determinants of somatic ageing. The public health implications of rethinking menopause as the by-product rather than the catalyst of biological ageing are discussed.

Biological determinism continues to rest on belief rather than evidence. The racial genetics of David Reich and his immediate predecessors exemplify science applied as racist ideology which obscures evidence for social criticism and moral accountability for inequity.

This article discusses four features of islands that make them places of special importance to environmental conservation. First, investment in island conservation is both urgent and cost-effective. Islands are threatened hotspots of diversity that concentrate unique cultural, biological and geophysical values, and they form the basis of the livelihoods of millions of islanders. Second, islands are paradigmatic places of human–environment relationships. Island livelihoods have a long tradition of existing within spatial, ecological and ultimately social boundaries and are still often highly dependent on local resources and social cohesion. Island cultures and their rich biocultural knowledge can be an important basis for revitalizing and innovating sustainable human–nature relationships. Third, islands form a global web that interlinks biogeographic regions and cultural spaces. They are nodes in a global cultural network: as multicultural island societies, through diaspora islander communities on continents and through numerous political and trade relationships among islands and between islands and countries on continents. Fourth, islands can serve as real-world laboratories that enable scientific innovation, integration of local and generalized knowledge and social learning and empowerment of local actors. We conclude that island systems can serve as globally distributed hubs of innovation, if the voices of islanders are better recognized.