英语考试作文-GRE写作Issue部分精品素材分享之生物多样性的指标

1、文档编码 : CS2R8Q4A7F5 HI7Y6V8Q5W7 ZI9H10M4N3Y2英语考试作文GRE写作 Issue 部分精品素材共享之生物多 样性的指标想要在 GRE作文部分的考试中写出优秀的文章,论据素材是重要的一环；好的论据不仅能帮忙你支撑观点,加强说服力,仍能表达出考生在阅读量上的积存和深厚扎实的语言功底基础；特别是 ISSUE作文,更是需要大量好素材作为储备,才能保证考生无论遭受那种题目, 都能游刃有余地完成一篇高分作文的写作；为大家整理了 GRE ISSUE作文各类题目的精品优质素材, 一起来看吧；生物多样性测量的三大指标richness Biodiversity is usu

2、ally plotted as taxonomic of a geographic area, with some reference to a temporal scale. Whittaker described three common metrics used to measure species-level biodiversity, encompassing attention to species richness or species evenness: 1. Species richnessthe least sophisticated of the indices avai

3、lable 2. Simpson index 3. Shannon index There are three other indices which are used by ecologists: 1. Alpha diversity refers to diversity within a particular area, community or ecosystem, and is measured by counting the number of taxa within the ecosystem usually species. 2. Beta diversity is speci

4、es diversity between ecosystems; this involves comparing the number of taxa that are unique to each of the ecosystems. 3. Gamma diversity is a measure of the overall diversity for different ecosystems within a region. 生物多样性的衡量Biodiversity is a broad concept, so a variety of objective measures have b

5、een created in order to empirically measure biodiversity. Each measure of biodiversity relates to a particular use of the data. For practical conservationists, this measure should quantify a value that is broadly shared among locally affected people. For others, a more economically defensible defini

6、tion should allow the ensuring of continued possibilities for both adaptation and future use by people, assuring environmental sustainability. As a consequence, biologists argue that this measure is likely to be associated with the variety of genes. Since it cannot always be said which genes are mor

7、e likely to prove beneficial, the best choice for conservation is to assure the this persistence of as many genes as possible. For ecologists, latter approach is sometimes considered too restrictive, as it prohibits ecological succession. 生物多样性与立法Biodiversity is beginning to be evaluated and its evo

8、lution analyzed through observations, inventories, conservation. as well as being taken into account in political and judicial decisions. The relationship between law and ecosystems is very ancient and has consequences for biodiversity. It is related to property rights, both private and public. It can define protection for threatened ecosystems, but also some rights and duties for example, fishing rights, hunting rights. Law regarding species is a more recent issue. It defines species that must be protected because