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In order to formulate animal feeding programs, zoos traditionally borrow knowledge and techniques, developed for domesticated animals, from livestock industry. Although livestock industry provides some of the basic components of feeding it is aimed at economic gain from animals, and the number of species it covers is extremely small. Moreover, wild animals are forced to make considerable adjustments to captivity in all aspects of life, and limitations of domesticated animal models should be recognized and examined. There exists a dire need to increase utilization of knowledge on food habits of wild animals acquired by field biologists, in our effort to improve zoo animal husbandry. Natural history attracts limited interest by zoos. However, it offers a wealth of information which needs to be explored to benefit zoo animal feeding practices.  相似文献   

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In order to formulate animal feeding programs, zoos traditionally borrow knowledge and techniques, developed for domesticated animals, from livestock industry. Although livestock industry provides some of the basic components of feeding it is aimed at economic gain from animals, and the number of species it covers is extremely small. Moreover, wild animals are forced to make considerable adjustments to captivity in all aspects of life, and limitations of domesticated animal models should be recognized and examined. There exists a dire need to increase utilization of knowledge on food habits of wild animals acquired by field biologists, in our effort to improve zoo animal husbandry. Natural history attracts limited interest by zoos. However, it offers a wealth of information which needs to be explored to benefit zoo animal feeding practices.  相似文献   

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李敏 《生命世界》2012,(4):94-95
在美国纽约曼哈顿区有一座博物馆,它独占中央公园西侧,用22座建筑物组成了一个自然历史殿堂,这就是有口皆碑的纽约自然历史博物馆。该博物馆建立于1869年,有50多个展厅,收藏着人类有史以来的各种植物、动物和矿物标本3600万件之多,现陈列有天文、矿物、人类、古动物和现代动物5个方面12个学部。就收藏标本之富,涵盖学科面之广,都无愧为世界最大的博物馆之一。  相似文献   

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The nuclear reactions occurring in the cores of stars which are believed to produce the element oxygen are first described. Evidence for the absence of free oxygen in the early atmosphere of the earth is reviewed. Mechanisms of creation of atmospheric oxygen by photochemical processes are then discussed in detail. Uncertainty regarding the rate of diffusion of water vapor through the cold trap at 70 km altitude in calculating the rate of the photochemical production of oxygen is avoided by using data for the concentration of hydrogen atoms at 90 km obtained from the Meinel OH absorption bands. It is estimated that the present atmospheric oxygen content could have been produced five to ten times during the earth's history. It is shown that the isotopic composition of atmospheric oxygen is not that of photosynthetic oxygen. The fractionation of oxygen isotopes by organic respiration and oxidation occurs in a direction to enhance the O18 content of the atmosphere and compensates for the O18 dilution resulting from photosynthetic oxygen. Thus, an oxygen isotope cycle exists in nature.  相似文献   

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A Guide to the Natural History of Freshwater Lake Bacteria   总被引:11,自引:0,他引:11  
Summary: Freshwater bacteria are at the hub of biogeochemical cycles and control water quality in lakes. Despite this, little is known about the identity and ecology of functionally significant lake bacteria. Molecular studies have identified many abundant lake bacteria, but there is a large variation in the taxonomic or phylogenetic breadths among the methods used for this exploration. Because of this, an inconsistent and overlapping naming structure has developed for freshwater bacteria, creating a significant obstacle to identifying coherent ecological traits among these groups. A discourse that unites the field is sorely needed. Here we present a new freshwater lake phylogeny constructed from all published 16S rRNA gene sequences from lake epilimnia and propose a unifying vocabulary to discuss freshwater taxa. With this new vocabulary in place, we review the current information on the ecology, ecophysiology, and distribution of lake bacteria and highlight newly identified phylotypes. In the second part of our review, we conduct meta-analyses on the compiled data, identifying distribution patterns for bacterial phylotypes among biomes and across environmental gradients in lakes. We conclude by emphasizing the role that this review can play in providing a coherent framework for future studies.  相似文献   

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On Fertile Ground:. Natural History of Human Reproduction. Peter T. Ellison. Cambridge, MA: Harvard University Press, 2001. 358 pp.  相似文献   

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1 Technology of natural materials Early man used conveniently shaped stones as tools. "Workshop" areas have been found with large numbers of stones, some showing signs of being worked. However, organic materials like wood will decay under normal wet conditions in the presence of oxygen, so we won't find the same sort of evidence for wooden tools. It is safe to assume that early man used sticks as probes and clubs, and maybe even for making some sort of nestlike protection against the elements and predators, since we see chimpanzees and other animals doing this sort of thing. So wood, and ahnost certainly other plant materials such as fibrous leaves, and bone and other materials gleaned from dead animals, would be used from the earliest times. We need to know this in order to establish the idea that Man can be expected to have a long history of the use and manipulation of natural materials. This needs skills in choosing materials for certain uses on the basis of their mechanical properties, whether those properties are to do with the ease of shaping the material or the effectiveness of that material in use. Occasionally the material was chosen simply because it was readily available. If we find that a particular material was always used for a certain job, it's reasonable to deduce that Man was exerting materials selection criteria through experience.  相似文献   

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