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111.
The relevance of evolutionary theory to ethics goes back to Darwin but until recently discussion employed evolutionary theory to justify ethical, social and political positions. Recently, evolutionary theory has been used to explain the existence of moral systems and moral propensities and, thereby, to provide a naturalistic basis for ethics. I argue that this approach has advanced our understanding of the basis of moral systems and moral propensities but does not as yet adequately incorporate the role of cognition in its account. Cognition has the effect of decoupling to some extent — though, of course, far from fully — human moral systems from their evolutionary origins. In an adequate account, evolutionary theory will play a crucial role but so also will our evolved cognitive abilities.  相似文献   
112.
KJ 85-06项目是“八五”期间由中国科学院资助的最大的生态学研究计划.19个研究所、20个试验站、530余名科技人员参加了该项计划,5年总经费1000万元.研究工作取得了重大进展,迄今已发表论文450余篇、专着3部,尚有大量论文与多部专着将陆续出版.本文简要介绍了有关主要研究进展,并就生态系统优化管理研究和生态过程、人类活动影响联网研究提出了两点主张.  相似文献   
113.
黑河流域中游地区净初级生产力的人类占用   总被引:2,自引:0,他引:2  
基于Miami模型,对黑河流域中游净初级生产力的人类占用(HANPP)及其与生态系统多样性的关系进行了研究,并对HANPP与生态足迹(EF)指标在可持续发展评估方面的价值进行了比较.结果表明:HANPP的提高将降低生态系统多样性,研究区现状年的平均HANPP率为38.61%,肃州区和甘州区的HANPP已超过生态系统潜在生产能力的极限;结合气候变化和社会经济发展状况进行分析,未来40年黑河流域中游生态系统将面临更大压力.与生态足迹(EF)相比,HANPP更适于从生态系统功能变化角度评估区域发展的可持续性.  相似文献   
114.
Integral projection models (IPMs) are extremely flexible tools for ecological and evolutionary inference. IPMs track the distribution of phenotype in populations through time, using functions describing phenotype‐dependent development, inheritance, survival and fecundity. For evolutionary inference, two important features of any model are the ability to (i) characterize relationships among traits (including values of the same traits across ages) within individuals, and (ii) characterize similarity between individuals and their descendants. In IPM analyses, the former depends on regressions of observed trait values at each age on values at the previous age (development functions), and the latter on regressions of offspring values at birth on parent values as adults (inheritance functions). We show analytically that development functions, characterized this way, will typically underestimate covariances of trait values across ages, due to compounding of regression to the mean across projection steps. Similarly, we show that inheritance, characterized this way, is inconsistent with a modern understanding of inheritance, and underestimates the degree to which relatives are phenotypically similar. Additionally, we show that the use of a constant biometric inheritance function, particularly with a constant intercept, is incompatible with evolution. Consequently, current implementations of IPMs will predict little or no phenotypic evolution, purely as artefacts of their construction. We present alternative approaches to constructing development and inheritance functions, based on a quantitative genetic approach, and show analytically and through an empirical example on a population of bighorn sheep how they can potentially recover patterns that are critical to evolutionary inference.  相似文献   
115.
116.
Abstract: Considering habitat selection at multiple scales is essential to fully understand habitat requirements and management needs for wildlife species of concern. We used a hierarchical information-theoretic approach and variance decomposition techniques to analyze habitat selection using local-scale habitat variables measured in the field and landscape-scale variables derived with a Geographic Information System (GIS) for nesting greater sage-grouse (Centrocercus urophasianus) in the Powder River Basin (PRB), Montana and Wyoming, USA, 2003–2007. We investigated relationships between habitat features that can and cannot be mapped in a GIS to provide insights into interpretation of landscape-scale—only GIS models. We produced models of habitat selection at both local and landscape scales and across scales, yet multiscale models had overwhelming statistical and biological support. Variance decomposition showed that local-scale measures explained the most pure variation (50%) in sage-grouse nesting-habitat selection. Landscape-scale features explained 20% of pure variation and shared 30% with local-scale features. Both local- and landscape-scale habitat features are important in sage-grouse nesting-habitat selection because each scale explained both pure and shared variation. Our landscape-scale model was accurate in predicting priority landscapes where sage-grouse nests would occur and is, therefore, useful in providing landscape context for management decisions. It accurately predicted locations of independent sage-grouse nests (validation R2 = 0.99) and showed good discriminatory ability with >90% of nests located within only 40% of the study area. Our landscape-scale model also accurately predicted independent lek locations. We estimated twice the amount of predicted nesting habitat within 3 km of leks compared to random locations in the PRB. Likewise we estimated 1.8 times more predicted nesting habitat within 10 km of leks compared to random locations. These results support predictions of the hotspot theory of lek placement. Local-scale habitat variables that cannot currently be mapped in a GIS strongly influence sage-grouse nest-site selection, but only within priority nesting habitats defined at the landscape scale. Our results indicate that habitat treatments for nesting sage-grouse applied in areas with an unsuitable landscape context are unlikely to achieve desired conservation results.  相似文献   
117.
目的探讨双歧杆菌脂磷壁酸与5-氟尿嘧啶(5-Fu)联用对H22荷瘤小鼠的抗肿瘤作用及免疫功能的影响。方法双歧杆菌脂磷壁酸单独或联合5-Fu处理H22荷瘤Balb/c小鼠,定期测量肿瘤大小,观察小鼠一般状况;计算抑瘤率、血红细胞数和白细胞数,取脾和胸腺计算脏器指数;HE染色分析肿瘤组织变化;MTT法检测小鼠脾T淋巴细胞增殖转化功能以及ELISA法检测小鼠脾淋巴细胞分泌IFN-γ含量。结果双歧杆菌脂磷壁酸及5-Fu单独应用均可抑制肿瘤生长,但单独5-Fu处理组小鼠一般状况差,毒性反应重;双歧杆菌脂磷壁酸与5-Fu联合应用,与单独5-Fu处理组比较,不仅抑瘤率明显提高(P〈0.01),且荷瘤小鼠一般状况改善,白细胞数升高,脏器指数增加,小鼠脾T淋巴细胞增殖能力强,脾淋巴细胞分泌IFN-γ,水平提高;光镜观察HE染色瘤体组织,双歧杆菌脂磷壁酸处理组可见大量炎症细胞浸润。结论双歧杆菌脂磷壁酸联合5-FU能增强化疗的抑瘤作用,并能扭转化疗引起的免疫低下现象,起到增效减毒作用。  相似文献   
118.
Conifer trees are routinely manipulated hormonally to increase flowering, branching, or adjust crown shape for production purposes. This survey of internal cytokinin levels provides a background for such treatments in Abies nordmanniana, a tree of great economic interest. Reference points in the crown and root system were sampled destructively in 4- and 6-year-old trees and analyzed for a range of cytokinins by LC-MS/MS. No seasonal patterns were detected in the root samples, and a major portion of cytokinin was in conjugated forms. Dramatic and consistent seasonal changes occurred in the crown, at levels 17–65 times higher than in the root. Predominant among crown cytokinins was ZR, except in the needles where IPR was also prominent. Within the crown, cytokinin profiles in different organs differed consistently. The leader bud showed a pronounced mid-June minimum, and a maximum later in summer. Subapical buds showed the same June minimum but peaked in mid autumn at a much lower level. Maxima in these buds were preceded by peaks in the subapical stem. Parallel patterns were observed in homologous tissues on branches.This pattern is consistent with two surges beginning in the uppermost stem tissues leading to subsequent accumulation or stimulated production within the buds. Strong differential hormonal profiles between adjacent buds with different fates agree with recent evidence of localized cytokinin production. The data suggest a reduced role of root-derived cytokinins in crown development. Practical cytokinin treatments for crown-shape regulation require close attention to dosage as well as precise timing and positioning.  相似文献   
119.
松褐天牛六种类型的触角感器的超微结构   总被引:2,自引:0,他引:2  
利用扫描电镜和透射电镜对松褐天牛Monochamus alternatus Hope不同类型触角感器的超微结构进行了观察和研究。在松褐天牛触角上存在6种类型的感器:机械感器、锥形感器、毛型感器、耳形感器、刺形感器和栓锥形感器。机械感器壁厚无孔,淋巴腔中无树突。锥形感器壁薄多孔,有50多个树突分支,每个分支有1~10个微管。毛型感器单壁,壁上有小孔,孔数相对较少,感器内树突1~8个不等,树突内含不同数量的微管。耳形感器,壁薄多孔,内部有少于5个的树突分支,树突内含有数量不等的微管。刺形感器又分为2个亚型:Ⅰ型壁上具纵脊无孔,顶端有孔;Ⅱ型壁上无脊无孔,顶端具单孔。刺形感器Ⅰ型和Ⅱ型均壁厚无孔,树突鞘一直通到顶端小孔。栓锥形感器上半部具纵脊无孔,下端有少量孔,顶端具三瓣状开口的孔。对感受器功能的讨论认为:机械感器不是化学感器;锥形、毛型和耳形感器是嗅觉感器;刺形和栓锥形感器可能是接触化学(味觉)感器。  相似文献   
120.
Abstract. Question: What are the grazing effects in the spatial organization and the internal structure of high and low cover patches from a two‐phase vegetation mosaic? Location: Patagonian steppe, Argentina. Methods: We mapped vegetation under three different grazing conditions: ungrazed, lightly grazed and heavily grazed. We analysed the spatial patterns of the dominant life forms. Also, in each patch type, we determined density, species composition, richness, diversity, size structure and dead biomass of grasses under different grazing conditions. Results: The vegetation was spatially organized in a two‐phase mosaic. High cover patches resulted from the association of grasses and shrubs and low cover patches were represented by scattered tussock grasses on bare ground. This spatial organization was not affected by grazing, but heavy grazing changed the grass species involved in high cover patches and reduced the density and cover of grasses in both patch types. Species richness and diversity in high cover patches decreased under grazing conditions, whereas in low cover patches it remained unchanged. Also, the decrease of palatable grasses was steeper in high cover patches than in low cover patches under grazing conditions. Conclusions: We suggest that although grazing promotes or inhibits particular species, it does not modify the mosaic structure of Patagonian steppe. The fact that the mosaic remained unchanged after 100 years of grazing suggests that grazing does not compromize population processes involved in maintaining patch structure, including seed dispersal, establishment or biotic interactions among life forms.  相似文献   
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