Telomeres are protective structures at the ends of eukaryotic chromosomes. The loss of telomeres through cell division and oxidative stress is related to cellular aging, organismal growth and disease. In this way, tel...Telomeres are protective structures at the ends of eukaryotic chromosomes. The loss of telomeres through cell division and oxidative stress is related to cellular aging, organismal growth and disease. In this way, telomeres link molecular and cellular mechanisms with organismal processes, and may explain variation in a number of important life-history traits. Here, we discuss how telomere biology relates to the study of physiological ecology and life history evolution. We emphasize current knowledge on how telomeres may relate to growth, survival and lifespan in natural populations. We finish by examining interest- ing new connections between telomeres and the glucocorticoid stress response. Glucocorticoids are often employed as indices of physiological condition, and there is evidence that the glucocorticoid stress response is adaptive. We suggest that one way that glucocorticoids impact organismal survival is through elevated oxidative stress and telomere loss. Future work needs to establish and explore the link between the glucocorticoid stress response and telomere shortening in natural populations. If a link is found, it provides an explanatory mechanism by which environmental perturbation impacts life history trajectories [Current Zoology 56 （6）： 714-727, 2010].展开更多
Our ecosystem provides us with essential services, most of which come without a price tag and hence are assumed to be ＂free gifts of nature＂ available in plenty. Much of the neoclassical thought and analysis was bas...Our ecosystem provides us with essential services, most of which come without a price tag and hence are assumed to be ＂free gifts of nature＂ available in plenty. Much of the neoclassical thought and analysis was based on this assumption until recently. The dynamic rise in population due to rapid industrialisation and urbanization has caused the realisation that ecosystem services are also limited. Environmental degradation is a common term used to describe the loss or impairment of ecosystem services. Migration is often a consequence of environ- mental degradation; when ecosystem services are impaired and survival comes at stake. But is the degradation of essential ecosystem services sufficient to motivate people to relocate？ Through a review of literature on migration and environmental degradation, this paper strives to answer the above question along with exploring ways how monitoring the deterioration of the environment on time can spare human inhabitants of any ecosystem the pains of migration in search of better means of survival and sustenance.展开更多
Aims The Nihewan Basin of North China,considered the cradle of Eastern civilization,contains a set of late Cenozoic strata and artifacts used by Homo ereettvs in the early Pleistocene(〜1.66 Ma to 780 ka)and the crania...Aims The Nihewan Basin of North China,considered the cradle of Eastern civilization,contains a set of late Cenozoic strata and artifacts used by Homo ereettvs in the early Pleistocene(〜1.66 Ma to 780 ka)and the cranial bones and teeth of early H.sapiens from the late middle Pleistocene(~370 to 260 ka).Palynological studies provide an opportunity to explore the living environment of early humans.Methods Ralynological samples from the Hutouliang Section(-603-587 ka)of the Xiaodukou Formation of the Nihewan Basin were treated by heavy liquid flotation.Based on the palynological assemblages from the section,vegetation and climate in the Nihewan Basin were reconstructed.Important Findings The dynamic vegetation changed from temperate needle-and broad-leaved mixed forest-steppe(mainly Picea,Abies,Betula,luglans,Artemisia and Chenopodiaceae)to conifer forest(mainly Pinus,Picea and Abies),which saw the replacement of H.erectus by early H.sapiens.The comparison of the Nihewan Basin with other human sites around the world during the same period reveals that early humans preferred to live in caves,accompanied by relatively open steppe or forest-steppe environments,inhabited by numerous mammals.Therefore,it is inferred that the emergence of dense conifer forest and the disappearance of open steppe environments in the Nihewan Basin at approximately 603-587 ka provide new evidence that early humans followed most mammals to steppe or forest-steppe environments and thus left the Nihewan Basin.These new findings not only enrich our knowledge of early human behavior,such as their diet,migration and settlement,but also fill in gaps in paleovegetation and paleoenvironmental research in the Nihewan Basin during the middle Pleistocene(780-400 ka).展开更多
文摘Telomeres are protective structures at the ends of eukaryotic chromosomes. The loss of telomeres through cell division and oxidative stress is related to cellular aging, organismal growth and disease. In this way, telomeres link molecular and cellular mechanisms with organismal processes, and may explain variation in a number of important life-history traits. Here, we discuss how telomere biology relates to the study of physiological ecology and life history evolution. We emphasize current knowledge on how telomeres may relate to growth, survival and lifespan in natural populations. We finish by examining interest- ing new connections between telomeres and the glucocorticoid stress response. Glucocorticoids are often employed as indices of physiological condition, and there is evidence that the glucocorticoid stress response is adaptive. We suggest that one way that glucocorticoids impact organismal survival is through elevated oxidative stress and telomere loss. Future work needs to establish and explore the link between the glucocorticoid stress response and telomere shortening in natural populations. If a link is found, it provides an explanatory mechanism by which environmental perturbation impacts life history trajectories [Current Zoology 56 （6）： 714-727, 2010].
文摘Our ecosystem provides us with essential services, most of which come without a price tag and hence are assumed to be ＂free gifts of nature＂ available in plenty. Much of the neoclassical thought and analysis was based on this assumption until recently. The dynamic rise in population due to rapid industrialisation and urbanization has caused the realisation that ecosystem services are also limited. Environmental degradation is a common term used to describe the loss or impairment of ecosystem services. Migration is often a consequence of environ- mental degradation; when ecosystem services are impaired and survival comes at stake. But is the degradation of essential ecosystem services sufficient to motivate people to relocate？ Through a review of literature on migration and environmental degradation, this paper strives to answer the above question along with exploring ways how monitoring the deterioration of the environment on time can spare human inhabitants of any ecosystem the pains of migration in search of better means of survival and sustenance.
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB26000000).
文摘Aims The Nihewan Basin of North China,considered the cradle of Eastern civilization,contains a set of late Cenozoic strata and artifacts used by Homo ereettvs in the early Pleistocene(〜1.66 Ma to 780 ka)and the cranial bones and teeth of early H.sapiens from the late middle Pleistocene(~370 to 260 ka).Palynological studies provide an opportunity to explore the living environment of early humans.Methods Ralynological samples from the Hutouliang Section(-603-587 ka)of the Xiaodukou Formation of the Nihewan Basin were treated by heavy liquid flotation.Based on the palynological assemblages from the section,vegetation and climate in the Nihewan Basin were reconstructed.Important Findings The dynamic vegetation changed from temperate needle-and broad-leaved mixed forest-steppe(mainly Picea,Abies,Betula,luglans,Artemisia and Chenopodiaceae)to conifer forest(mainly Pinus,Picea and Abies),which saw the replacement of H.erectus by early H.sapiens.The comparison of the Nihewan Basin with other human sites around the world during the same period reveals that early humans preferred to live in caves,accompanied by relatively open steppe or forest-steppe environments,inhabited by numerous mammals.Therefore,it is inferred that the emergence of dense conifer forest and the disappearance of open steppe environments in the Nihewan Basin at approximately 603-587 ka provide new evidence that early humans followed most mammals to steppe or forest-steppe environments and thus left the Nihewan Basin.These new findings not only enrich our knowledge of early human behavior,such as their diet,migration and settlement,but also fill in gaps in paleovegetation and paleoenvironmental research in the Nihewan Basin during the middle Pleistocene(780-400 ka).
