Question

Since English biologist Charles Darwin published On the Origin of Species in 1859, scientists have vastly improved their knowledge of natural history. However, a lot of information is still of the speculation, and scientists can still only make educated guesses at certain things.

One subject that they guess about is why some 400 million years ago, animals in the sea developed limbs (肢) that allowed them to move onto and live on land.

Recently, an idea that occurred to the US paleontologist (古生物学家) Alfred Romer a century ago became a hot topic once again.

Homer thought that tidal (潮汐的) pools might have led to fish gaining limbs. Sea animals would have been forced into these pools by strong tides. Then, they would have been made either to adapt to their new environment close to land or die. The fittest among them grew to accomplish the transition (过渡) from sea to land.

Romer called these earliest four-footed animals “tetrapods”. Science has always thought that this was a credible theory, but only recently has there been strong enough evidence to support it.

Hannah Byrne is an oceanographer (海洋学家) at Uppsala University in Sweden. She announced at the 2018 Ocean Sciences Meeting in Oregon, US, that by using computer software, her team had managed to link Homer’s theory to places where fossil deposits (沉积物) of the earliest tetrapods were found.

According to the magazine Science, in 2014, Steven Balbus, a scientist at the University of Oxford in the UK, calculated that 400 million years ago, when the move from land to sea was achieved, tides were stronger than they are today. This is because the planet was 10 percent closer to the moon than it is now.

The creatures stranded in the pools would have been under the pressure of “survival of the fittest”, explained Mattias Green, an ocean scientist at the UK’s University of Bangor. As he told Science, “After a few days in these pools, you become food or you run out of food... the fish that had large limbs had an advantage because they could flip (翻转) themselves back in the water.”

As is often the case, however, there are others who find the theory less convincing. Cambridge University’s paleontologist Jennifer Clark, speaking to Nature magazine, seemed unconvinced. “It’s only one of many ideas for the origin of land-based tetrapods, any or all of which may have been a part of the answer,” she said.

1.Who first proposed the theory that fish might have gained limbs because of tidal pools?

A. Alfred Romer.    B. Charles Darwin.

C. Hannah Byrne.    D. Steven Balbus.

2.Why were tides stronger 400 million years ago than they are today according to Steven Balbus?

A. There were larger oceans.

B. Earth was closer to the moon.

C. The moon gave off more energy.

D. Earth was under greater pressure.

3.The underlined word “stranded” in Paragraph 8 probably means “________”.

A. found    B. settled

C. abandoned    D. trapped

4.What is the focus of the article?

A. The arguments over a scientific theory.

B. The proposal of a new scientific theory.

C. Some new evidence to support a previous theory.

D. A new discovery that questions a previous theory.

Answer

1.A

2.B

3.D

4.C

【解析】本文为一篇科学报道。文章用一些新的证据来支持先前人们的猜测理论：即海洋中的动物是因为潮汐的作用导致鱼类发展出四肢，迁徙到陆地的。

1.细节理解题。根据第三Recently, an idea that occurred to the US paleontologist (古生物学家) Alfred Romer a century ago became a hot topic once again.和四段第一句“Homer thought that tidal (潮汐的) pools might have led to fish gaining limbs.”可知，是Alfred Romer最先提出了鱼类可能因为潮汐而发展出四肢的理论。故选A项。

2.细节理解题。根据第七段最后“…tides were stronger than they are today. This is because the planet was 10 percent closer to the moon than it is now.（过去的潮汐比现在强。这是因为地球这颗行星以前比现在离月球近了10%。）可知，B项正确。

3.猜测词义题。根据第4段中的Sea animals would have been forced into these pools by strong tides. 可知，Homer认为海洋生物因为潮汐被迫进入水池。第8段第一句“The creatures stranded in the pools would have been under the pressure of “survival of the fittest”, explained Mattias Green,“ 结合两处可知，鱼儿是被迫进入池中，那就不是被发现（A. found）或被遗弃（C. abandoned），鱼儿也不想定居在（B. settled），而是被困于池中（D. trapped）最为适合题意，故选D项。

4.主旨大意题。根据文章全文可知，英国生物学家达尔文的《物种起源》极大地提高了科学家对自然的认识。但仍有不少没有根据的猜测。其中的一个猜测就是为什么在4亿年前，海洋中的动物有了四肢，从而让他们迁徙到陆地上生活。一个世纪以前，美国古生物学家Alfred Romer提出的一个想法，即潮汐可能导致鱼类发展出四肢，这再次成为一个热门话题。针对此许多科学家进行的实验提供了许多新的证据来证实它。C项（一些新的证据来支持先前的理论。）是文章的关注点，故选C。