Quarterly Review of Biology

Fever, the rise in body temperature set point in response to infection or injury, is a highly conserved trait among vertebrates, and documented in many arthropods. Fever is known to reduce illness duration and mortality. These observations present an evolutionary puzzle: why has fever continued to be an effective response to fast-evolving pathogenic microbes across diverse phyla, and probably over countless millions of years? Framing fever as part of a more general thermal manipulation strategy that we term defensive hyperthermia, we hypothesize that the solution lies in the independent contributions to pathogen fitness played by virulence and infectivity...

Ant mill, caterpillar circle, bat doughnut, amphibian vortex, duck swirl, and fish torus are different names for rotating circular animal formations, where individuals turn around a common center. These "collective vortex behaviors" occur at different group sizes from pairs to several million individuals and have been reported in a large number of organisms, from bacteria to vertebrates, including humans. However, to date, no comprehensive review and synthesis of the literature on vortex behaviors has been conducted...

Organisms adapt developmental and physiological features to local and transient conditions in part by modulating transcription, translation, and protein functions, usually without changing DNA sequences. Remarkably, these epigenetic changes sometimes endure through meiosis and gametogenesis, thereby affecting phenotypic variation across generations, long after epigenetic changes were triggered. Transgenerational effects challenge our traditional understanding of inheritance. In this review, we focus on patterns of inheritance, molecular features, mechanisms that lead from environmental and genetic perturbations to phenotypic variation in later generations, and issues about study design and replication...

The geographic distributions of all species are limited, and the determining factors that set these limits are of fundamental importance to the fields of ecology and evolutionary biology. Plant and animal ranges have been of primary concern, while those of parasites, which represent much of the Earth's biodiversity, have been neglected. Here, we review the determinants of the geographic ranges of parasites and pathogens, and explore how parasites provide novel systems with which to investigate the ecological and evolutionary processes governing host/parasite spatial distributions...

Evolutionary theory predicts rigorous competition in nature and selfish behavior is thus seen as its inevitable consequence. Evidence of altruistic and cooperative behavior therefore appears at odds with evolutionary theory. However, evolutionary psychology suggests that past environments may be different from the current environments that humans inhabit. Here it is hypothesized that competition in two past environments might have led to strategies that favored altruism and cooperation toward nonkin. First, the expansion of the human brain is seen as requiring long-term, quality parental investment to sustain it...

Microbial model systems have made major contributions across the life sciences. Their influence extends beyond strictly microbiological research to inform and enhance general biological understanding. To cast light on how microbial populations and communities function as model systems, we examine their use in historical and contemporary research on evolutionary and ecological dynamics. We assess the pros and cons of microbial model systems, and identify specific ways in which they benefit research. Analyzing microbial model systems is of particular value as biologists become increasingly aware of the microbial world and its interactions with the rest of life...

ABSTRACT We propose that plant foods containing high quantities of starch were essential for the evolution of the human phenotype during the Pleistocene. Although previous studies have highlighted a stone tool-mediated shift from primarily plant-based to primarily meat-based diets as critical in the development of the brain and other human traits, we argue that digestible carbohydrates were also necessary to accommodate the increased metabolic demands of a growing brain. Furthermore, we acknowledge the adaptive role cooking played in improving the digestibility and palatability of key carbohydrates...

Some adaptationist explanations are regarded as maximally solid and others fanciful just-so stories. Just-so stories are explanations based on very little evidence. Lack of evidence leads to circular-sounding reasoning: "this trait was shaped by selection in unseen ancestral populations and this selection must have occurred because the trait is present." Well-supported adaptationist explanations include evidence that is not only abundant but selected from comparative, populational, and optimality perspectives, the three adaptationist subdisciplines...

Broadening contingents of ecologists and environmental scientists have recently begun to promote ecological resilience both as a conceptual framework and as a practical goal. As some critics have noted, this growing interest has brought with it a multiplication of notions of ecological resilience. This paper reviews how and why the notion of ecological resilience has been adopted, used, and defended in ecology since its introduction by C. S. Holling in 1973. We highlight the many faces of ecological resilience, but unlike other reviewers who see these as disunified and confused, we interpret ecological resilience as an evolving, multidimensional, theoretical concept unified by its role in guiding practical response to ecological and environmental challenges...

Most developmental biologists equate tunicates to the sessile ascidians, including Ciona intestinalis, and the pelagic appendicularians, in particular Oikopleura dioica. However, there exists a third group of tunicates with a pelagic lifestyle, the thaliaceans, which include salps, pyrosomes, and doliolids. Although thaliaceans have raised the curiosity offamous zoologists since the 18th century, the difficulty of observing and experimentally manipulating them has led to many controversies and speculations about their life cycles and developmental strategies, the phylogenetic relationship within the group and with other tunicates, and the drivers of speciation in these widely distributed animals living in a seemingly uniform environment...

Ecological succession is arguably the most enduring contribution of plant ecologists and its origins have never been contested. However, we show that French entomologist Pierre Mégnin, while collaborating with medical examiners in the late 1800s, advanced the first formal definition and testable mechanism of ecological succession. This discovery gave birth to the twin disciplines of carrion ecology and forensic entomology. As a novel case of multiple independent discovery, we chronicle how the disciplines of plant and carrion ecology (including forensic entomology) accumulated strikingly similar parallel histories and contributions...

Environmental sex reversal (ESR), which results in a mismatch between genotypic and phenotypic sex, is well documented in numerous fish species and may be induced by chemical exposure. Historically, research involving piscine ESR has been carried out with a view to improving profitability in aquaculture or to elucidate the processes governing sex determination and sexual differentiation. However, recent studies in evolution and ecology suggest research on ESR now has much wider applications and ramifications...

Paradoxically, men report better health and quality of life than women, but men experience higher mortality rates than women at most ages. One conclusion from these findings is that men have been selected to disregard signs of ill health, or even to deceive themselves about their health, to their detriment because presenting themselves as healthy has fitness benefits. We hypothesize that men have been sexually selected to present themselves to women as healthy but that the cost of not attending to their minor health problems results in earlier mortality than women...

No abstract text is available yet for this article.

Turning points in science occur when an issue has reached maturity, when a critical mass of new facts cries out for a new synthesis, and when there is a general sense of urgency to reconsider basic assumptions" (von der Malsburg et al. 2010:xiii).

Beginning with Darwin, some have argued that predation on other vertebrates dates to the earliest stages of hominid evolution, and can explain many uniquely human anatomical and behavioral characters. Other recent workers have focused instead on scavenging, or particular plant foods. Foraging theory suggests that inclusion of any food is influenced by its profitability and distribution within the consumer's habitat. The morphology and likely cognitive abilities of Ardipithecus, Australopithecus, and early Homo suggest that while hunting and scavenging occurred, their profitability generally would have been considerably lower than in extant primates and/or modern human hunter-gatherers...

For almost 40 years, studies of whole-organism performance have formed a cornerstone of evolutionary physiology. Although its utility as a heuristic guide is beyond question, and we have learned much about morphological evolution from its application, the ecomorphological paradigm has frequently been applied to performance evolution in ways that range from unsatisfactory to inappropriate. More importantly, the standard ecomorphological paradigm does not account for tradeoffs among performance and other traits, nor between performance traits that are mediated by resource allocation...

Many models of evolution calculate the rate of evolution by multiplying the rate at which new mutations originate within a population by a probability of fixation. Here we review the historical origins, contemporary applications, and evolutionary implications of these "origin-fixation" models, which are widely used in evolutionary genetics, molecular evolution, and phylogenetics. Origin-fixation models were first introduced in 1969, in association with an emerging view of "molecular" evolution. Early origin-fixation models were used to calculate an instantaneous rate of evolution across a large number of independently evolving loci; in the 1980s and 1990s, a second wave of origin-fixation models emerged to address a sequence of fixation events at a single locus...

Several unresolved issues, paradoxes, and information voids characterize the field of evolution of aging. The recent discovery of aging-like phenomenon in Escherichia coli, marked by asymmetric segregation of damaged components, particularly protein aggregates, has created a number of new possibilities that remain underexplored. Bacterial systems can potentially throw light on issues such as: whether evolution of aging and evolution of death are different phenomena; whether aging is inevitable for life or is an evolved strategy; whether there could be selection for aging or aging is a pleiotropic effect of some other selection; what are the possible mechanisms of antagonistic pleiotropy, if any; and whether there are mechanisms of aging that are conserved throughout the hierarchy of life...

A unified system of bioenergetic parameters that describe thermal regulation and energy metabolism in many passerine and non-passerine species has been developed. These parameters have been analyzed as functions of ambient temperature, and bioenergetic models for various species have been developed. The level of maximum food energy or maximal existence metabolism (MPE) is 1.3 times higher in passerines than in non-passerines, which is consistent with the ratio of their basal metabolic rates (BMR). The optimal ambient temperature for maximizing productive processes (e...