鲨鱼知道长寿的秘密

所属教程:金融时报原文阅读

浏览:

2020年08月07日

手机版

扫描二维码方便学习和分享

鲨鱼知道长寿的秘密

地球上最长寿脊椎动物很可能是鲨鱼——最近在格陵兰岛附近的北冰洋域发现小头睡鲨，年纪最大的已有400多岁。

测试中可能遇到的词汇和知识：

stalk 追踪，潜近[stɔːk]

specimen 样品，样本；标本['spesɪmɪn]

vertebrate 脊椎动物['vɜːtɪbrət]

succor 救援物品['sʌkɚ]

snare 捕捉；诱惑[sneə]

radiocarbon [核] 放射性碳[,reɪdɪəʊ'kɑːb(ə)n]

sobering 使清醒的['səʊbərɪŋ]

intone 吟诵；吟咏[ɪn'təʊn]

mishap 灾祸；不幸事故['mɪshæp]

mammalian 哺乳类动物的[mæ'meɪlɪən]

immortality 不朽；不朽的声名；不灭[ɪmɔː'tælɪtɪ]

elixir 不老长寿药；万能药；炼金药[ɪ'lɪksə; -sɪə]

abstinence 节制；节欲；戒酒；禁食['æbstɪnəns]

eternal 永恒的；不朽的[ɪ'tɜːn(ə)l; iː-]

阅读马上开始，建议您计算一下阅读整篇文章所用的时间，对照下方的参考值就可以评估出您的英文阅读水平。

如果您读完全文用时为：那么，您的阅读速度相当于每分钟阅读的英文单词数

4分19秒母语为英语者的朗读速度 140

2分6秒母语为英语的中学生的阅读速度 250

1分55秒母语为英语的大学生的阅读速度 350

0分1秒母语为英语的速读高手 1000

Sharks hold secret to a longer life（615words）

By Anjana Ahuja

-----------------------------------------------------

There are Methuselahs among us. These aged wonders of the natural world do not stalk the earth but glide through Arctic waters. Scientists surveying Greenland sharks, previously thought to live up to 200 years, found that they have far longer lifespans. One specimen was calculated, give or take a century, to be nearly 400 years old, born more than a century before the US was founded.

The discovery, reported last week in the journal Science, is a record for a vertebrate, and potentially gives succour to those searching for the secrets of longevity. Anti-ageing enthusiasts insist that life is merely the absence of the processes that lead to death, and that human lifespan could be extended dramatically. Their philosophy is to treat ageing as a disease: treat the disease and life need not end.

Sharks and rays usually reveal their ages through the calcium deposits laid down each year in hard structures such as fins, but Greenland sharks, the largest fish in northern waters, have no such structures. Instead, researchers, presented with 28 females snared accidentally in fishing nets, looked to sharks’ eye lenses. Tissues formed in the lens at birth remain unchanged; its radiocarbon (a radioactive isotope of carbon) content can be matched to the known levels of radiocarbon in the marine environment stretching back 500 years. In effect, a shark’s eye lens contains a radiocarbon time-stamp of its birth.

An international team, led by academics at the University of Copenhagen, showed that the largest sharks — one stretched to 5m — were generally the oldest, with one dated at about 392 years old. The females are estimated to reach sexual maturity at 156. Their eyes also provide a sobering window on human history: the lenses of the youngest fishes contained a “bomb pulse”, a distinctive radiocarbon signature resulting from nuclear weapons testing.

The study intones, rightly, that we should guard these centenarians of the deep; their leisurely pace of maturity and reproduction has obvious consequences for conservation. But it also shows there are potentially many longer-lived species than humans, raising questions anew about whether there really is any natural bar to humans living for centuries. After all, life expectancy has been rising for decades as we conquer the challenges — malnutrition, disease, war, mishap — that hasten our passing. Three centuries ago, a person would be hard pushed to reach 40; some scientists think those born today stand a fighting chance of reaching 150.

Currently, the Japanese are the flag-bearers, boasting a life expectancy of 83 (life expectancy is the average age reached by a population; lifespan is the number of years lived by a particular individual). The longest verified lifespan is 122 years. Humans are not going to outlive sharks any time soon, but new records are being set in mammalian species. This year, scientists found that mice could be engineered to live 35 per cent longer simply by clearing ageing cells from the body. Such laboratory breakthroughs have transformed the quest for immortality from laughing stock to biotech stock. The mission statement of Calico, an Alphabet-backed life sciences start-up, has been paraphrased as “curing death”. Human Longevity, a company focusing on genome research into ageing, boasts a stellar line-up of backers. Meanwhile, hedge fund manager Joon Yun has set up the $1m Palo Alto Longevity prize to “hack the code” for ageing.

In the absence of an elixir, there is some evidence, albeit mixed, that cutting calories may extend life in mice and monkeys. Members of the Calorie Restriction Society advocate partial abstinence as the route to long life. I suspect, however, that forgoing chips and chocolate cake simply makes life feel longer than it really is, and is instead the secret of eternal boredom.

请根据你所读到的文章内容，完成以下自测题目：

1. Which kind of sharks can live about 400 years?

A. goblin sharks

B. hammerhead sharks

C. greenland sharks

D. thresher sharks

2. What do scientists find in shark’s eye lens to know sharks’ lifespan?

A. sodium

B. radiocarbon

C. iodine

D. potassium

3. When are the female sharks estimated to reach sexual maturity?