甘肅 王玲秀

人們普遍認為沙漠是所有生命的禁區(qū)，然而，研究人員發(fā)現，在干燥的沙漠地帶，竟然還生存著魚類……

篇幅：362詞 難度：★★★ 建議用時：7分鐘?

1How life manages to continue in unpredictable and extreme environments is a major question in evolution. For aquatic (水生的) animals, extreme environments include those with little water, such as the deserts of Central Australia.

2Researchers believe that the ability to adapt the environment can ensure the populations of desert fish survive in difficult conditions. They focused on populations of Desert Rainbowfish collected from across the Australian desert and found that populations from drier regions of the desert are more isolated (隔絕的) and smaller, but also show stronger capacity to adapt to tough and dry environments. This turns on its head traditional thinking that small populations are evolutionary dead ends. Life finds a way, even in the most extreme and unpredictable environments on the Earth.

3Genetic diversity helps populations evolve in response to environmental changes,so maintaining a large gene pool is very important, but understanding how small populations of desert fish survive, especially when located in isolated pockets of water, has remained a mystery.

4Generally speaking, a small gene pool can lead to inbreeding and poor health,which is sometimes seen in endangered species. However, researchers have found that desert fish in Australia can hold on to life through adapting to tough environments,breeding and spreading during rare flooding events.

5The genes adapted to the drought can spread when the fish migrate along temporary streams and floodwaters. These fish and their adapted genetic make-up are then ready for the next drought. The most attractive difference is in a gene coding for the proteins that are used in fish for taste and smell. They can be used to find out water flow and control light sensitivity for vision. The different protein in fish from the western parts of drought areas may improve their environmental sensors.

6Genes adapted to drought may allow species to keep existing as dry regions expand and have more extreme environmental changes under future climate change. The results of the recent study suggest that adaptations of genetic diversity can take place even in small populations, as long as natural connectivity during floods takes place. The findings that small populations can evolve in extreme environments have some influence on studies of adaptation to climate change and conservation science.

Reading Check

Language Study

Ⅰ. Difficult sentence in the text

However, researchers have found that desert fish in Australia can hold on to life through adapting to tough environments, breeding and spreading during rare flooding events. 然而，研究人員發(fā)現，澳大利亞的沙漠魚可以通過適應惡劣環(huán)境來維持生命，在罕見的洪水暴發(fā)期繁殖和擴散。

【點石成金】本句中，that引導賓語從句；through adapting to tough environments為介詞短語作狀語；breeding and spreading during rare flooding events為非謂語動詞作結果狀語。

Ⅱ. Text-centered chunks

adapt to 適應

turn sth on its head 使人完全改變思路；使人從反面思考

in response to 對……做出反應

generally speaking 一般說來

lead to 導致

as long as 只要

take place 發(fā)生

have some influence on 對……有一些影響