“classification”的概念、定义、翻译、参考文献-科学参考

classification

Biology

The arrangement of organisms into a series of groups based on physiological, biochemical, anatomical, or other relationships. An artificial classification is based on one or a few characters simply for ease of identification or for a specific purpose; for example, birds are often arranged according to habit and habitat (seabirds, songbirds, birds of prey, etc.) while fungi may be classified as edible or poisonous. Such systems do not reflect evolutionary relationships. A natural classification is based on resemblances and is a hierarchical arrangement. The smallest group commonly used is the species. Species are grouped into genera (see genus), the hierarchy continuing up through tribes, families, orders, classes, and phyla (see phylum) to kingdoms and, in some systems, to domains. In traditional systems of plant classification the phylum was replaced by the division. Higher up in the hierarchy the similarities between members of a group become fewer. Present-day natural classifications try to take into account as many features as possible and in so doing aim to reflect the phylogeny of organisms, i.e. the history of their evolutionary relationships (see cladistics). Natural classifications are also predictive. Thus if an organism is placed in a particular genus because it shows certain features characteristic of the genus, then it can be assumed it is very likely to possess most (if not all) of the other features of that genus. See also binomial nomenclature; molecular systematics; taxonomy.

Geology and Earth Sciences

1. Any scheme for structuring data that is used to group individuals. In ecological and taxonomic studies numerical classification schemes have been devised, but various hierarchical or non-hierarchical classificatory strategies have also been used. In taxonomy, the fundamental unit is the species. Among living forms species are groups of individuals that look alike and can interbreed, but cannot interbreed with other species. In palaeontology, where breeding capability cannot be determined, species are defined according to morphological similarities. In formal nomenclature, taxonomists follow the binomial system developed by the Swedish naturalist Carolus Linnaeus (1707–78). In this system each species is defined by two names: the generic (referring to the genus) and the specific (referring to the species). Thus various related species may share a common generic name. Genera (sing. genus) may be combined with others to form families, and related families combined into an order. Orders may be combined into classes, and classes into phyla (sing. phylum) or divisions in the case of Plantae (although this level is omitted in modern angiosperm classification). For example, the brachiopods comprise some eleven orders split between two classes and these two classes are the major subdivisions of the phylum Brachiopoda. The basic groupings, the phyla, are combined together into kingdoms, e.g. Plantae (the plants), Fungi, and Animalia (animals), and the kingdoms into domains. Some workers have tackled the uncertainties arising from subjectivity in classification by using numerical methods. In their view, if enough characters were measured and represented by cluster statistics, the distances between clusters could be used as a measure of difference. Even so, the worker has to decide (subjectively) how best to analyse the measurements, and so objectivity is lost. Other workers emphasize those features shared by organisms that show a hierarchical pattern (see cladistics).
2. In remote sensing, the computer-assisted recognition of surface materials. The process assigns individual pixels of an image to categories (e.g. vegetation, road) based on spectral characteristics compared to spectral characteristics of known parts of an image (training areas). Assignation of pixels is not always possible when the parameter space of different training areas overlaps. In such cases a principal component analysis prior to classification may be used to allow better separation of training areas by increasing the overall parameter space. See also box classification; minimum-distance-to-means classification; maximum-likelihood classification.

Geography

It is important to remember that ‘classification is not just a neutral activity’ (R. Inkpen, 2005). The classifier looks for groups of like phenomena/objects that can be treated as a single unit for the purpose of making valid generalizations about aspects. Clearly, many different classifications are possible, depending on the purpose of the study being undertaken: ‘streams, for example, form a single class, but they can be subdivided on a variety of criteria, such as order, depth, gradient, and so on. The purpose of classification procedures is to provide a grouping which is valid for the scientific activity being undertaken: criteria for classification must first be determined, and then the objects measured on these must be allocated to classes’ (R. J. Johnston, 1976).
Geography uses a range of classificatory systems: intrinsic classification depends on natural differences or ‘breaks’ in the features studied; extrinsic classification uses arbitrarily defined class limits; monothetic classification uses one criterion; polythetic classification uses a number of criteria; attribute-based classification is based on ‘present’ or ‘absent’ evidence (a climate may or may not have a dry season); variable-based classification forms classes on the basis of the degree to which a variable is present.

单词	classification
释义	classification Biology The arrangement of organisms into a series of groups based on physiological, biochemical, anatomical, or other relationships. An artificial classification is based on one or a few characters simply for ease of identification or for a specific purpose; for example, birds are often arranged according to habit and habitat (seabirds, songbirds, birds of prey, etc.) while fungi may be classified as edible or poisonous. Such systems do not reflect evolutionary relationships. A natural classification is based on resemblances and is a hierarchical arrangement. The smallest group commonly used is the species. Species are grouped into genera (see genus), the hierarchy continuing up through tribes, families, orders, classes, and phyla (see phylum) to kingdoms and, in some systems, to domains. In traditional systems of plant classification the phylum was replaced by the division. Higher up in the hierarchy the similarities between members of a group become fewer. Present-day natural classifications try to take into account as many features as possible and in so doing aim to reflect the phylogeny of organisms, i.e. the history of their evolutionary relationships (see cladistics). Natural classifications are also predictive. Thus if an organism is placed in a particular genus because it shows certain features characteristic of the genus, then it can be assumed it is very likely to possess most (if not all) of the other features of that genus. See also binomial nomenclature; molecular systematics; taxonomy. Geology and Earth Sciences 1. Any scheme for structuring data that is used to group individuals. In ecological and taxonomic studies numerical classification schemes have been devised, but various hierarchical or non-hierarchical classificatory strategies have also been used. In taxonomy, the fundamental unit is the species. Among living forms species are groups of individuals that look alike and can interbreed, but cannot interbreed with other species. In palaeontology, where breeding capability cannot be determined, species are defined according to morphological similarities. In formal nomenclature, taxonomists follow the binomial system developed by the Swedish naturalist Carolus Linnaeus (1707–78). In this system each species is defined by two names: the generic (referring to the genus) and the specific (referring to the species). Thus various related species may share a common generic name. Genera (sing. genus) may be combined with others to form families, and related families combined into an order. Orders may be combined into classes, and classes into phyla (sing. phylum) or divisions in the case of Plantae (although this level is omitted in modern angiosperm classification). For example, the brachiopods comprise some eleven orders split between two classes and these two classes are the major subdivisions of the phylum Brachiopoda. The basic groupings, the phyla, are combined together into kingdoms, e.g. Plantae (the plants), Fungi, and Animalia (animals), and the kingdoms into domains. Some workers have tackled the uncertainties arising from subjectivity in classification by using numerical methods. In their view, if enough characters were measured and represented by cluster statistics, the distances between clusters could be used as a measure of difference. Even so, the worker has to decide (subjectively) how best to analyse the measurements, and so objectivity is lost. Other workers emphasize those features shared by organisms that show a hierarchical pattern (see cladistics). 2. In remote sensing, the computer-assisted recognition of surface materials. The process assigns individual pixels of an image to categories (e.g. vegetation, road) based on spectral characteristics compared to spectral characteristics of known parts of an image (training areas). Assignation of pixels is not always possible when the parameter space of different training areas overlaps. In such cases a principal component analysis prior to classification may be used to allow better separation of training areas by increasing the overall parameter space. See also box classification; minimum-distance-to-means classification; maximum-likelihood classification. Geography It is important to remember that ‘classification is not just a neutral activity’ (R. Inkpen, 2005). The classifier looks for groups of like phenomena/objects that can be treated as a single unit for the purpose of making valid generalizations about aspects. Clearly, many different classifications are possible, depending on the purpose of the study being undertaken: ‘streams, for example, form a single class, but they can be subdivided on a variety of criteria, such as order, depth, gradient, and so on. The purpose of classification procedures is to provide a grouping which is valid for the scientific activity being undertaken: criteria for classification must first be determined, and then the objects measured on these must be allocated to classes’ (R. J. Johnston, 1976). Geography uses a range of classificatory systems: intrinsic classification depends on natural differences or ‘breaks’ in the features studied; extrinsic classification uses arbitrarily defined class limits; monothetic classification uses one criterion; polythetic classification uses a number of criteria; attribute-based classification is based on ‘present’ or ‘absent’ evidence (a climate may or may not have a dry season); variable-based classification forms classes on the basis of the degree to which a variable is present.
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