DOES YOUR HOSPITAL NEED A RECOVERY ROOM?

In a survey made to estimate the need for a special room in which patients could recover from anesthesia after operation, it was found that of 475 cases in which this service might have been used, it would have been desirable in 296; that recovery room care would probably have relieved ward nurses of the duty of special care during their busiest hours; that recovery room care was indicated in a high percentage of cases in which certain anesthetics were employed, and that the need for recovery room care appeared to increase in proportion to the amount of pre-sedation given.     

WHY DOES A METHOD THAT FAILS CONTINUE TO BE USED?

As a critical framework for addressing a diversity of evolutionary and ecological questions, any method that provides accurate and detailed phylogeographic inference would be embraced. What is difficult to understand is the continued use of a method that not only fails, but also has never been shown to work--nested clade analysis is applied widely even though the conditions under which the method will provide reliable results have not yet been demonstrated. This contradiction between performance and popularity is even more perplexing given the recent methodological and computational advances for making historical inferences, which include estimating population genetic parameters and testing different biogeographic scenarios. Here I briefly review the history of criticisms and rebuttals that focus specifically on the high rate of incorrect phylogeographic inference of nested-clade analysis, with the goal of understanding what drives its unfettered popularity. In this case, the appeal of what nested-clade analysis claims to do--not what the method actually achieves--appears to explain its paradoxical status as a favorite method that fails. What a method promises, as opposed to how it performs, must be considered separately when evaluating whether the method represents a valuable tool for historical inference.     

DOES A NORMAL FOETUS REALLY HAVE A FUTURE OF VALUE? A REPLY TO MARQUIS

The traditional approach to the abortion debate revolves around numerous issues, such as whether the foetus is a person, whether the foetus has rights, and more. Don Marquis suggests that this traditional approach leads to a standoff and that the abortion debate 'requires a different strategy.' Hence his 'future of value' strategy, which is summarized as follows: (1) A normal foetus has a future of value. (2) Depriving a normal foetus of a future of value imposes a misfortune on it. (3) Imposing a misfortune on a normal foetus is prima facie wrong. (4) Therefore, depriving a normal foetus of a future of value is prima facie wrong. (5) Killing a normal foetus deprives it of a future value. (6) Therefore, killing a normal foetus is prima facie wrong. In this paper, I argue that Marquis's strategy is not different since it involves the concept of person--a concept deeply rooted in the traditional approach. Specifically, I argue that futures are valuable insofar as they are not only dominated by goods of consciousness, but are experienced by psychologically continuous persons. Moreover, I argue that his strategy is not sound since premise (1) is false. Specifically, I argue that a normal foetus, at least during the first trimester, is not a person. Thus, during that stage of development it is not capable of experiencing its future as a psychologically continuous person and, hence, it does not have a future of value.     

DOES LARGE BODY SIZE IN MALES EVOLVE TO FACILITATE FORCIBLE INSEMINATION? A STUDY ON GARTER SNAKES

A trend for larger males to obtain a disproportionately high number of matings, as occurs in many animal populations, typically is attributed either to female choice or success in male-male rivalry; an alternative mechanism, that larger males are better able to coercively inseminate females, has received much less attention. For example, previous studies on garter snakes (Thamnophis sirtalis parietalis) at communal dens in Manitoba have shown that the mating benefit to larger body size in males is due to size-dependent advantages in male-male rivalry. However, this previous work ignored the possibility that larger males may obtain more matings because of male-female interactions. In staged trials within outdoor arenas, larger body size enhanced male mating success regardless of whether a rival male was present. The mechanism involved was coercion rather than female choice, because mating occurred most often (and soonest) in females that were least able to resist courtship-induced hypoxic stress. Males do physically displace rivals from optimal positions in the mating ball, and larger males are better able to resist such displacement. Nonetheless, larger body size enhances male mating success even in the absence of such male-male interactions. Thus, even in mating systems where males compete physically and where larger body size confers a significant advantage in male-male competition, the actual selective force for larger body size in males may relate to forcible insemination of unreceptive females. Experimental studies are needed to determine whether the same situation occurs in other organisms in which body-size advantages have been attributed to male-male rather than male-female interactions.     

DOES FISH ECOLOGY PREDICT DISPERSAL ACROSS A RIVER DRAINAGE DIVIDE?

Obligate freshwater taxa are frequently distributed among catchments isolated by marine and terrestrial barriers. Such distributions can arise through vicariant changes in drainage geometry, or dispersal via intermittent freshwater connections. We employed two adjacent rivers in southern New Zealand to test for interdrainage dispersal while controlling for historical drainage geometry, and analyzed four ecologically distinct freshwater-limited fish taxa to assess any relationship with habitat preference. Individuals from the Mararoa and Oreti catchments (n >100 per species) were sequenced for a minimum of 1297 bp of mitochondrial DNA (cytochrome b and control region). Phylogeographic relationships were consistent with ecological expectations of interdrainage dispersal capability, with the two obligate riverine taxa each exhibiting reciprocal monophyly between catchments, whereas the two facultative swamp dwellers revealed paraphyletic relationships, one of which shared a haplotype between catchments. Statistical phylogeography, accommodating taxon-specific mutation rates and the known age of the last major riverine connection between these catchments, rejected complete isolation of populations for one of the swamp dwellers. Therefore, dispersal across a young (145-240 kyr) drainage divide is inferred for one species, and can be predicted to some extent by species ecology. Moreover, our study highlights the importance of historical drainage geometry when assessing the causes of contemporary genetic structuring in freshwater taxa.     

THE SIGNIFICANCE OF OUTCROSSING IN AN INTIMATE PLANT-HERBIVORE RELATIONSHIP. II. DOES OUTCROSSING POSE A PROBLEM FOR THRIPS ADAPTED TO THE HOST-PLANT CLONE?

The thrips herbivore Apterothrips apteris reproduces both sexually and parthenogenetically and exhibits fine-scale local adaptation to individual phenotypes of its host plant, Erigeron glaucus. We ask whether we can disrupt the ability of thrips to use progeny of their “home”-plant clone by outcrossing females with males from other plant clones. We compare the performance of sexually produced thrips to that of parthenogenetically produced thrips on plant progeny of the home clone. Because we use thrips from plant clones experiencing both high and low infestations by thrips, we also ask whether the relative performance of “sexuals” versus “parthenogens” differs with the infestation level of the home clone. Plant progeny of 10 E. glaucus clones were either the product of selfing or of outcrossing with the other 9 clones. We have shown in previous work that selfing preserved the parental phenotype with respect to attack by thrips. Because of this result, we predicted that parthenogens should fare better than sexuals on the selfed progeny of the home-plant clone. Our results, however, showed the contrary: sexuals outperformed parthenogens on these selfed plants. We also found that plant characters appear to influence thrips performance more than the mating system of thrips. We found no evidence for outbreeding depression in this system.     

ENDOSYMBIOTIC CALCIFYING BACTERIA: A NEW CUE TO THE ORIGIN OF CALCIFICATION IN METAZOA?

Sponges show the highest diversity of associated bacteria among marine invertebrates. Immunological evidence traces the origin of the sponge bacterial symbioses to the Precambrian era. Hence, sponges appear to be ideally suited for studying the evolutionary origins of prokaryote–metazoan associations. Sponges produce either calcareous or siliceous skeletons, which only coexist in a relict group of demosponges, the sclerosponges. We report here, for the first time, intensive calcification in nonsclerosponge siliceous demosponges. Calcification is mediated by endosymbiotic bacteria (calcibacteria) located in archeocyte‐like sponge cells. These calcibacteria are devoid of bacterial walls and divide within sponge cells until they became surrounded by a calcitic sheet, being subsequently extruded to the sponge subectosomal (subepithelial) zone. Thousands of bacteria‐produced calcitic spherules cover the surface of the host sponges, forming a cortex‐like structure that mimics a rudimentary peripheral skeleton. Calcibacteria are vertically transferred to the sponge larvae during embryogenesis. Calcium detoxification may have generated this symbiotic association, with some additional benefits for the sponges, such as skeletal formation and deterrence from predation. This unique symbiosis holds implications for sponge biology and may advance discussions on the role of bacteria in early biocalcification processes in metazoans.     

PERSPECTIVE: GENETIC ASSIMILATION AND A POSSIBLE EVOLUTIONARY PARADOX: CAN MACROEVOLUTION SOMETIMES BE SO FAST AS TO PASS US BY?

Abstract.— The idea of genetic assimilation, that environmentally induced phenotypes may become genetically fixed and no longer require the original environmental stimulus, has had varied success through time in evolutionary biology research. Proposed by Waddington in the 1940s, it became an area of active empirical research mostly thanks to the efforts of its inventor and his collaborators. It was then attacked as of minor importance during the "hardening" of the neo-Darwinian synthesis and was relegated to a secondary role for decades. Recently, several papers have appeared, mostly independently of each other, to explore the likelihood of genetic assimilation as a biological phenomenon and its potential importance to our understanding of evolution. In this article we briefly trace the history of the concept and then discuss theoretical models that have newly employed genetic assimilation in a variety of contexts. We propose a typical scenario of evolution of genetic assimilation via an intermediate stage of phenotypic plasticity and present potential examples of the same. We also discuss a conceptual map of current and future lines of research aimed at exploring the actual relevance of genetic assimilation for evolutionary biology.