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In biology/ecology, parasitism is a non-mutual symbiotic relationship between species, where one species, the parasite, benefits at the expense of the other, the host. Traditionally ''parasite'' (in biological usage) referred primarily to organisms visible to the naked eye, or macroparasites (such as helminths). ''Parasite'' can include microparasites, which are typically smaller, such as protozoa, viruses, and bacteria.〔Claude Combes, ''The Art of being a Parasite'', U. of Chicago Press, 2005〕 Examples of parasites include the plants mistletoe and cuscuta, and animals such as hookworms. Unlike predators, parasites typically do not kill their host, are generally much smaller than their host, and will often live in or on their host for an extended period. Both are special cases of consumer-resource interactions. Parasites show a high degree of specialization, and reproduce at a faster rate than their hosts. Classic examples of parasitism include interactions between vertebrate hosts and tapeworms, flukes, the ''Plasmodium'' species, and fleas. Parasitism differs from the parasitoid relationship in that parasitoids generally kill their hosts.〔 (【引用サイトリンク】 The Differences Between Parasites and Parasitoids ) 〕〔 〕〔 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VRT-4CNT0D6-4&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_version=1&_urlVersion=0&_userid=10&md5=3c7a3e2fbf44ccce8f7e74d13c1a72a9 〕 Parasites reduce host biological fitness by general or specialized pathology, such as parasitic castration and impairment of secondary sex characteristics, to the modification of host behavior. Parasites increase their own fitness by exploiting hosts for resources necessary for their survival, e.g. food, water, heat, habitat, and transmission. Although parasitism applies unambiguously to many cases, it is part of a continuum of types of interactions between species, rather than an exclusive category. In many cases, it is difficult to demonstrate harm to the host. In others, there may be no apparent specialization on the part of the parasite, or the interaction between the organisms may remain short-lived. == Etymology == First used in English 1539, the word ''parasite'' comes from the Medieval French ''parasite'', from the Latin ''parasitus'', the latinisation of the Greek ''παράσιτος'' (''parasitos''), "one who eats at the table of another"〔(παράσιτος ), Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus Digital Library〕 and that from ''παρά'' (''para''), "beside, by"〔(παρά ), Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus Digital Library〕 + ''σῖτος'' (''sitos''), "wheat".〔(σῖτος ), Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus Digital Library〕 Coined in English in 1611, the word ''parasitism'' comes from the Greek ''παρά'' (''para'') + ''σιτισμός'' (''sitismos'') "feeding, fattening".〔(σιτισμός ), Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus Digital Library〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Parasitism」の詳細全文を読む スポンサード リンク
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