Population sequences in a high altitude alpine environment: Archaeological sites and historical and environmental time

Since 1998, a group of archaeologists have been studying the long-term history of human settlement and activity in the mid to high altitude (1800m and above) in theParc National des Ecrins (southern French Alps). This research has identified a number of different phases of settlement since the end of the last Ice Age (10,000 years ago). Whilst we accept that it is impossible to present the variation in actual number of people present in these marginal milieus, we can present an overview of waxing and waning of human activity in our study area. Our research demonstrates that poeple moved into these high altitude zones as soon as the glaciers retreated. The first phase of extensive and relatively intensive activity dates to the Bronze Age (c. 2000 BC). During the Iron Age and Roman period there appears to have been a relative reduction in the level of activity. However, from the early medieval period onwards there is incontrovertible evidence for a substantial increase in activity. This culminates with the emergence of a “busy” landscape during the post-medieval period when mining and pastoral activities were at their peak.     

Evolution of human growth spurts

This study investigates subadult growth spurts in a large sample of anthropoid primates, including humans. Analyses of body mass growth curves show that humans are not unique in the expression of female and male body mass growth spurts. Subadult growth spurts are observed in both New World and Old World anthropoid primates and are more common in males than in females. Allometric analyses of growth spurts indicate that many aspects of primate growth spurts are strongly correlated with species size. Small species tend not to exhibit growth spurts. Although male and female scaling patterns for velocity and size measures are comparable, scaling relations of variables that measure the timing of growth spurts differ by sex. These patterns can he related to sexual differences in life histories. Scaling analyses further show that humans do not depart substantially from patterns that describe other anthropoid primates. Thus, in relative terms, human growth spurts are not exceptional compared to this sample of primates. The long absolute delay in the initiation of the human growth spurt may be of substantial evolutionary importance and serves to distinguish humans from other primates. In essence, humans exhibit growth spurts that are comparable to other primates in many respects. However, human growth spurts are shifted to very late absolute ages. © 1996 Wiley-Liss, Inc.     

Ontogeny and the fossil record: what,if anything,is an adult dinosaur?

Identification of the ontogenetic status of an extinct organism is complex, and yet this underpins major areas of research, from taxonomy and systematics to ecology and evolution. In the case of the non-avialan dinosaurs, at least some were reproductively mature before they were skeletally mature, and a lack of consensus on how to define an ‘adult’ animal causes problems for even basic scientific investigations. Here we review the current methods available to determine the age of non-avialan dinosaurs, discuss the definitions of different ontogenetic stages, and summarize the implications of these disparate definitions for dinosaur palaeontology. Most critically, a growing body of evidence suggests that many dinosaurs that would be considered ‘adults’ in a modern-day field study are considered ‘juveniles’ or ‘subadults’ in palaeontological contexts.     

On the 'rate of aging' in heterogeneous populations

It is well known that the rate of aging is constant for populations described by the Gompertz law of mortality. However, this is true only when a population is homogeneous. In this note, we consider the multiplicative frailty model with the baseline distribution that follows the Gompertz law and study the impact of heterogeneity on the rate of aging in this population. We show that the rate of aging in this case is a function of age and that it increases in (calendar) time when the baseline mortality rate decreases.     

Effect of exposure to Echinostoma itliei miracidia on growth and survival of young Biomphalaria glabrata snails

Kuris A. M. 1980. Effect of exposure to Echinostoma liei miracidia on growth and survival of young Biomphalaria glabrata snails. International Journal for Parasitology10: 303–308. Exposure to miracidia of Echinostoma liei resulted in increased mortality and reduced growth of 1–2 mm albino Biomphalaria glabrata snails whether or not the snails became infected. Growth rates for infected and exposed but uninfected snails were significantly more variable than growth rates of unexposed snails. Retarded growth and increased mortality were detected as rapidly as seven to nine days after exposure. Neither growth nor survivorship of 4–6 mm snails was altered upon exposure to or infection by E. liei.     

Demography of Amboseli baboons, 1963–1983

Repeated censuses of a population of yellow baboons (Papio cynocephalus) in Amboseli National Park, Kenya, revealed a decrease from over 2,500 animals in 1963–1964 to 123 individuals in 1979, or from a density of about 73 to 1.8 baboons per km² over a 15-year period. Median group size decreased from 43 in 1964 to 27 in 1979. The largest and smallest groups declined the most; groups near the median have maintained fairly stable size and age distributions. The population seemed to have stabilized by 1983 at approximately 150 animals in six groups (median group size 28; density 2.2/km²). Although baboon population and group size appeared to be stable during 1963–1964, the age distribution and demographic parameters (age-specific mortality and natality for one social group) during that year indicate that the population decline had already started. The rate of population decline was greatest in the 1964–1969 period and remained appreciable during the next 5 years. The decline of the baboon population was paralleled by that of other Amboseli savannah woodland mammalian species and took place during a period of very high mortality of fever trees (Acacia xanthophloea) and extensive invasion of the area by halophytes, a transition brought on by rising ground water and consequent elevation of the soil salinity zone. In this and several other primate populations, mortality of infants and juveniles appears to be the demographic variable most sensitive to environmental change.     

Genes located on a SSC17 meat quality QTL region are associated with growth in outbred pig populations

The objective of this study was to evaluate the effect of markers developed in eight genes, located in a previously detected meat quality QTL region on SSC17, on growth, fat and meat quality traits collected in commercial pig populations of different genetic backgrounds. The genes had been previously mapped to SSC17 as part of a fine-mapping effort. Association analyses were conducted between each marker and the available phenotypic traits. Results showed that three genes ( CTSZ , CSTF1 and C20orf43 ) were significantly associated with the growth traits. In addition, CTSZ also impacted on meat colour, with the less favourable genotype for growth being associated with darker meat. The differences observed between genotypes were substantial and may be of economic importance to pig producers. These markers may be useful for selecting for faster growth or improved meat quality.     

Does hut climate matter for piglet survival in organic production?

Piglet mortality in outdoor production systems varies across the year, and a reason for this variation could be fluctuations in hut climate, as ambient temperature might influence piglet survival, both directly and indirectly. Therefore, the aim of the current study was to investigate the impact of farrowing hut climate and year variation on stillbirth and liveborn mortality. A large-scale observational study was conducted at five commercial organic pig-producing herds in Denmark from June 2015 to August 2016. Both year variation (F_3,635=4.40, P=0.004) and farrowing hut temperature (F_2,511=6.46, P=0.002) affected the rate of stillbirths. The risk of stillborn piglets was lowest in winter and during this season larger changes in hut temperature between day 1 prepartum and the day of farrowing increased the risk of stillbirths (F_1,99=6.39, P=0.013). In addition, during the warm part of the year stillbirth rate increased at temperatures ⩾27°C. Year variation also affected liveborn mortality (F_3,561=3.86, P=0.009) with a lower rate of liveborn deaths in spring. However, the hut climate did not influence liveborn deaths. Consequently, other factors than hut climate may explain the influence of year variation on liveborn mortality. These could be light differences causing seasonality in reproduction and lactation.