英语听力精选进阶版 13288

Earth may house 8.7 million species

Report

It's generally accepted that very many species have yet to be discovered, but until now nobody has devised a reliable way to find out just how many. Suggestions for total numbers have ranged from 3 million to a hundred million, but most of these have been no more than intelligent guesses. 

Scientists from the Census¹ of Marine² Life devised a counting method by identifying numerical patterns linking data on known species. They reckon that there should be about 8.7 million types of living organisms, three-quarters of them animals and the rest plants. 

However, since the introduction of the current classification system by Carl Linnaeus in 1758, only a million and a quarter have been catalogued. 

The scientists warn that human activity is hastening extinctions, and they note a touch wistfully, that many of the hitherto unknown species may vanish before we even know of their existence.

Paddy Clark, BBC News

1 census   

n.(官方的)人口调查，人口普查

参考例句：

• A census of population is taken every ten years.人口普查每10年进行一次。
• The census is taken one time every four years in our country.我国每四年一次人口普查。

2 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。