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21.
中缅树鼩静止代谢率的研究 总被引:17,自引:0,他引:17
测定了分布于我国云南高原的中缅树(Tupaiabelangeri)在不同环境温度下的静止代射率(每小时每克体重的耗氧量,YRMR)和体温调节能力.T.belangeri的体温为(37.6±0.15)℃(冬)和(38.7±0.13)℃(夏);体温受环境温度的影响较大;冬夏2季的下临界温度分别为27.5和30.0℃;热中性区内的静止代谢率(YBMR)是(1.56±0.03)mL·h-1·g-1(冬)和(1.94±0.09)mL·h-1·g-1(夏)为体重预期值的155.3%和182.6%.2季的YBMR没有显著差异;冷压下最低平均热传导(Cmin)冬夏2季分别为(0.1449±0,002)和(0.1860±0.01)mL·h-1·g-1·℃-1,为预期值的176.9%和199.9%,夏季显著高于冬季.T.belangeri在热能代谢和体温调节方面具有热带小型哺乳动物的特征,同时,又显示出某些适应于高原的特征。 相似文献
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It is possible to infer aspects of an organism's lifestyle from its gene content. Can the reverse also be done? Here we consider this issue by modelling evolution of the reduced genomes of endosymbiotic bacteria. The diversity of gene content in these bacteria may reflect both variation in selective forces and contingency-dependent loss of alternative pathways. Using an in silico representation of the metabolic network of Escherichia coli, we examine the role of contingency by repeatedly simulating the successive loss of genes while controlling for the environment. The minimal networks that result are variable in both gene content and number. Partially different metabolisms can thus evolve owing to contingency alone. The simulation outcomes do preserve a core metabolism, however, which is over-represented in strict intracellular bacteria. Moreover, differences between minimal networks based on lifestyle are predictable: by simulating their respective environmental conditions, we can model evolution of the gene content in Buchnera aphidicola and Wigglesworthia glossinidia with over 80% accuracy. We conclude that, at least for the particular cases considered here, gene content of an organism can be predicted with knowledge of its distant ancestors and its current lifestyle. 相似文献
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布氏田鼠空间分布格局 总被引:1,自引:0,他引:1
在鼠种群高密度时期,洞群为均匀分布.位于洞群中心的土丘通常被小叶锦鸡儿灌丛覆盖。分析布氏田鼠空间分布格局的适宜样方单位面积为10m×10m。鼠种群、雄鼠以及雌鼠都是聚集分布。繁殖季节,幼鼠以个体群为基本分布单元呈聚集分布,亚成体鼠以个体群为基本分布单元呈随机分布,成体鼠以个体为基本分布单元呈随机分布。布氏田鼠的聚集分布是由其繁殖方式和社群关系所致,而不太可能是栖息环境所致。鼠种群聚集分布强度从春到秋无显著性改变。 相似文献
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用网捕技术分析小龙门林场夏季小型森林鸟类群落的年动态 总被引:5,自引:0,他引:5
借助网捕方法进行鸟类群落的研究表明:至少连续3d的网捕才能获得鸟群落中绝大多数的物种,在网捕中应特别注意在鸟早、中、晚的3个活动高峰期间检查粘网,以及天气的影响,通过连续8a对北京小龙门林场小型森林鸟类群落的研究,发现其鸟群落物种数和生物量的年际变化不大,保持稳定,而群落的多样性和均匀性逐年上升。 相似文献
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White RS Smith LK Roberts AW Christie PA Kusznir NJ;iSIMM Team Roberts AM Healy D Spitzer R Chappell A Eccles JD Fletcher R Hurst N Lunnon Z Parkin CJ Tymms VJ 《Nature》2008,452(7186):460-464
When continents break apart, the rifting is sometimes accompanied by the production of large volumes of molten rock. The total melt volume, however, is uncertain, because only part of it has erupted at the surface. Furthermore, the cause of the magmatism is still disputed-specifically, whether or not it is due to increased mantle temperatures. We recorded deep-penetration normal-incidence and wide-angle seismic profiles across the Faroe and Hatton Bank volcanic margins in the northeast Atlantic. Here we show that near the Faroe Islands, for every 1 km along strike, 360-400 km(3) of basalt is extruded, while 540-600 km(3) is intruded into the continent-ocean transition. We find that lower-crustal intrusions are focused mainly into a narrow zone approximately 50 km wide on the transition, although extruded basalts flow more than 100 km from the rift. Seismic profiles show that the melt is intruded into the lower crust as sills, which cross-cut the continental fabric, rather than as an 'underplate' of 100 per cent melt, as has often been assumed. Evidence from the measured seismic velocities and from igneous thicknesses are consistent with the dominant control on melt production being increased mantle temperatures, with no requirement for either significant active small-scale mantle convection under the rift or the presence of fertile mantle at the time of continental break-up, as has previously been suggested for the North Atlantic Ocean. 相似文献
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从肥满度看布氏田鼠对气候环境的适应 总被引:4,自引:0,他引:4
布氏田鼠肥满度和气温、地表温、地下40 cm土层温度、降水量成显著性负相关,成年鼠对气候条件的适应范围宽于幼鼠.从肥满度角度来看,布氏田鼠能够较好地适应其生活环境. 相似文献
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野生断乳雄性小家鼠社会等级的形成无亲缘关系组早于亲缘关系组,判断未来优势和从属个体的行为学指标也因亲缘关系的影响而不同,在无亲缘关系组,未来优势鼠的嗅体和远处探究2种社会探究显著地高于未来从属鼠;在亲缘关系组,未来优势鼠直接和跳跃行为显著地多于未来从属鼠。 相似文献