研究顯示，有一個體積較大的大腦可能是造成一些大型哺乳動物滅絕的原因之一。這是因為大腦工作時需要消耗許多能量，再加上大腦體積大的動物通常有著較長的妊娠期，這也就意味著它們繁殖得很慢。本期《隨身英語》探討大體積大腦所引起的困擾。

課文內容

詞匯: 生物

Is it possible to be too clever? Could it be that a big brain is actually a dangerous asset?

Whilst the brainy human species goes from strength to strength, a study suggests that having an abundance of grey matter directly increases the risk of extinction in our mammal cousins.

Biologist Manuela Gonzalez-Suarez, from the University of Reading, says that big brains come with a clear downside.

"The cost is too high," she told BBC Future. They require a lot of energy to grow and maintain. Large-brained animals also have longer gestational periods, meaning they produce fewer offspring. And their young need greater parental attention until they become independent.

These traits mean "populations cannot grow fast, or quickly compensate for additional mortality," she says.

In short, big brains are an investment not all animals can afford. And this precarious situation is made worse by the fact that many large mammals are themselves the target of poaching or live in threatened habitats.

Some animals have long since decided that brains weren’t necessary. BBC Future suggests that sponges evolved to lose their brains over time, as they offered no tangible benefits.

But what about humans? We are the most intelligent species on Earth. We have tamed the natural environment, developed incredible technologies, and settled across almost every corner of the planet. But all this may be exacerbating the problem for other species.

Gonzalez-Suarez says: "It is our collective responsibility as scientists who study megafauna to act to prevent their decline." Time to put our big brains to good use.

詞匯表

asset 長處，優點
brainy 有頭腦的，聰明的
go from strength to strength 不斷壯大，從強大變得更強
grey matter（口語）大腦，智力
downside 不利之處
gestational period 妊娠期
offspring 后代，子孫
young 動物的幼小后代
trait 特質，特征
mortality 死亡率
precarious 危險的，不確定的
to poach 偷獵
habitat 動物的棲息地，生存環境
to evolve 進化
species 物種
to tame 控制，駕馭
to exacerbate 使惡化，使加劇
megafauna 巨型動物群

測驗與練習

1.  閱讀課文并回答問題。

1. Why are big brains 'expensive'?

2. Which phrase means 'shared duty'?

3. What does Gonzales-Suarez believe the scientific community should do about large animals?

4. Why did sponges lose their brains?

5. True or false? Mammals with big brains increase the risk of extinction for humans.

2.  請你在不參考課文的情況下完成下列練習。選擇一個意思合適的單詞填入句子的空格處 。

1. Being a famous, sexy, wealthy, popular celebrity does come with one big _________: you have no privacy. 

downside         asset         habitat         trait

2. A mother tiger protecting her _________ will viciously attack potential threats.

megafauna         habitat         young         species

3. Sponges _________ strength to strength since losing their brains.

gone from         go from         have gone from         are going to

4. If you tell him directly it will only _________ the problem. Find another way to let him know.

prevent         excruciate         evolve         exacerbate

5. She's the _________ person I know! Straight A-grades again last year.

biggest brained         brainiest         most brainy         brainest

答案

1.  閱讀課文并回答問題。

1. Why are big brains 'expensive'?
Big brains cost both energy and time. They require energy to grow and maintain. Animals with big brains also require a longer time in the womb and being cared for by their parents.

2. Which phrase means 'shared duty'?
Collective responsibility.

3. What does Gonzales-Suarez believe the scientific community should do about large animals?
She believes scientists should work together to prevent the decline of megafauna.

4. Why did sponges lose their brains?
According to the article, having a brain offered insufficient benefits for sponges.

5. True or false? Mammals with big brains increase the risk of extinction for humans.
False: Humans increase the risk of extinction for large mammals.

2. 請你在不參考課文的情況下完成下列練習。選擇一個意思合適的單詞填入句子的空格處 。

1. Being a famous, sexy, wealthy, popular celebrity does come with one big downside: you have no privacy.

2. A mother tiger protecting her young will viciously attack potential threats.

3. Sponges have gone from strength to strength since losing their brains.

4. If you tell him directly it will only exacerbate the problem. Find another way to let him know.

5. She's the brainiest person I know! Straight A-grades again last year.