We determined the mitochondrial DNA control region sequences of six Bucerotiformes. Hornbills have the typical avian gene order and their control region is similar to other avian control regions in ...that it is partitioned into three domains: two variable domains that flank a central conserved domain. Two characteristics of the hornbill control region sequence differ from that of other birds. First, domain I is AT rich as opposed to AC rich, and second, the control region is approximately 500 bp longer than that of other birds. Both these deviations from typical avian control region sequence are explainable on the basis of repeat motifs in domain I of the hornbill control region. The repeat motifs probably originated from a duplication of CSB-1 as has been determined in chicken, quail, and snowgoose. Furthermore, the hornbill repeat motifs probably arose before the divergence of hornbills from each other but after the divergence of hornbills from other avian taxa. The mitochondrial control region of hornbills is suitable for both phylogenetic and population studies, with domains I and II probably more suited to population and phylogenetic analyses, respectively.
We determined ringed seal (Pusa hispida) bacular and testicular growth relationships and made interspecific comparisons to species with better-known mating systems to elaborate on current hypotheses ...about the mating system of the ringed seal. We measured 161 bacula, 251 pairs of testes, and 55 mandibles collected from ringed seals of known age from Inuit subsistence harvests in Arviat and Sanikiluaq, Nunavut, Canada, from 2003 to 2006. Ringed seal bacular and testicular sizes were positively allometric relative to mandibular size for immature males (<7 years of age) but increased isometrically in mature males (≥7 years of age), similar to relationships between bacular size and body length for known polygynous pinnipeds. Adult isometric growth contrasted with harp seals (Pagophilus groenlandicus), a promiscuous species, in which bacular size likely is sexually selected. Our results, combined with previously reported ecological and behavioral ringed seal characteristics, suggest that ringed seals display a polygynous mating system.
Pinnipeds display a remarkable variation in life history adaptations while successfully inhabiting almost every marine environment. We explore how they have done this by grouping the world's pinniped ...species according to their environmental conditions, mating systems, lactation strategies, and timing of life histories. Next, we tested whether any of these clusters provide information about risk of extinction (using the International Union for Nature and the Conservation of Natural Resources status ranks). Seals at risk were not characterized by differences in lactation pattern (22% short vs. 46% long), mating system (24% multimale vs. 35% harems), or timing of life history events (23% fast vs. 42% slow) but did differ based on four environmental groupings. Grouping traits (rather than seals) described two clusters: one that included the environmental trait, primary productivity, and a second one that included all other environmental variables (seasonality, latitude, and temperature). Based on this result and theoretical considerations, we plotted seals according to energy (primary productivity) and variation (seasonality) and found a pattern analogous to that of the same four groups determined by cluster analysis of all environmental variables. Of the two pinniped groups representing low variation (equatorial and high productivity), ten of 21 seal species have been designated at risk, in contrast to none of the 13 seal species adapted to high variation. We conclude that seals appear to be best adapted to seasonal environments and thus, conservation efforts may benefit by concentrating on species inhabiting less variable environments.
During everyday social interactions, we typically anticipate (or explain) others' behaviour according to their current mental states (e.g. their knowledge, beliefs and intentions). To date, very ...little is known about the time-course with which such perspective information influences communication. We report a novel interactive ‘visual world’ study examining these processes. Here, two communicators watched videos depicting transfer events and subsequently described these events to each other. Critically, on half the trials a screen blocked the speakers' (but not the listeners') view part-way through the video, establishing a discrepancy in the knowledge held by the two communicators. Eye-tracking analyses showed that listeners were rapidly sensitive to their partner's perspective, as evidenced by a significantly reduced reality-bias when speakers held out-of-date knowledge about a privileged transfer event. However, we also found that under these conditions, listeners suffered ongoing interference from their own knowledge of reality, which inhibited successful anticipation of the speaker's intended referents.
► We examined the time-course of adult perspective-taking. ► We employed eye-tracking in a 2-person ToM task. ► We found that people were rapidly sensitive to others' perspectives. ► But, we also found evidence of ongoing interference due to a ‘pull of reality’.
Isotopic time series from sequentially sampled growth layer groups (GLGs) in marine mammal teeth can be combined to build chronologies allowing assessment of isotopic variation in marine ecosystems. ...Synchronous recording of baseline isotopic variation across dentinal GLGs of species with temporal and spatial overlap in foraging offers a unique opportunity for validation of marine mammal age estimation procedures through calibration of GLG deposition rates in one species against another whose GLG deposition has been independently determined. In this study, we compare trends in stable carbon isotope ratios (d13C) across dentinal GLGs of three eastern Canadian Arctic (ECA) beluga (Delphinapterus leucas) populations through the 1960s-2000s with a d13C time series measured across dentinal GLGs of ECA/Northwest Atlantic killer whales (Orcinus orca) from 1944-1999. We use confirmed annual GLG deposition in killer whales as a means to assess beluga GLG deposition, and show linear d13C declines across chronologies of both species were statistically indistinguishable when based on annual GLG deposition in beluga whales, but differed when based on biannual deposition. We suggest d13C declines reflect the oceanic 13C Suess effect, and provide additional support for annual GLG deposition in beluga whales by comparing rates of d13C declines across beluga GLGs with published annual d13C declines attributed to the oceanic 13C Suess effect in the North Atlantic.
This study aimed to provide further evidence of validity and reliability for the Physical Education Teacher Attitudes toward Fitness Tests Scale (PETAFTS), which consisted of affective and cognitive ...domains. There were two subdomains in the affective domain (i.e., enjoyment of implementing fitness tests and enjoyment of using test results) and one domain in the cognitive domain (i.e., beliefs in the usefulness of test results). Full-time physical education teachers (N = 469) from two southwestern states in the United States participated in the study. Reliability and validity of the scale were examined. Alphas were computed for the entire 16-item scale, the affective and cognitive domains, and the two subdomains, respectively, to test the reliability. Confirmatory factor analysis (CFA) was employed to investigate the construct validity. The commonly used CFA indices, such as the chi square (χ
2
), the comparative fit index (CFI), the Tucker-Lewis Index (TLI), the goodness of fit index (GFI), and the root mean square error of approximation (RMSEA), were used to assess the fit of the data to the model. The CFA results suggested that the data from the study did not fit the original model proposed by
Keating and Silverman (2004b)
, resulting in the elimination of item 3. The fitness of the data to the model was improved and deemed acceptable. More studies on the reliability and validity of the scale are needed in the future in order to use the scale with more confidence.
Life‐history theory allows predictions of how changes in environmental selection pressures along a species' geographic distribution result in discrete shifts in life‐history traits. We tested for ...spatial patterns of 24 populations of brown bears Ursus arctos across North America that grouped according to the following environmental and population parameters: evapotranspiration as a correlate of primary productivity of vegetation, coefficient of variation of monthly evapotranspiration values as a measure of seasonality. population density, and adult female weight. Cluster analysis grouped brown bear populations into two regions: Pacific‐coastal populations characterized by high population density and large females that lived in areas of high primary productivity and low seasonality. and inland and barren‐ground populations characterized by relatively low density and small bears that lived in areas of low productivity and high seasonality. For each region, we tested whether life‐history traits (age at maturity and interbirth interval) related to primary productivity or seasonality. High altitude (interior: > 1000 m) and high latitude (barren‐ground; >65°N) populations respond to extremes in seasonality with risk‐spreading adaptations. For example, age at maturity and interbirth interval increased with greater seasonality. In contrast, Pacific‐coastal populations living on the western edge of brown bear geographic range respond to intraspecific competition at high densities by maximizing offspring competitive ability. For example, age at maturity increased with greater primary productivity and high population density. In each region, the female parent decided on the life‐history trade‐offs required to reduce the risks of offspring mortality depending on the environmental pattern.
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