人教全日制普通高中英语（必修）高三UNIT4-2

 In his youth Charles Darwin enjoyed all the freedom to experiment and do whatever he liked. The study of physics, chemistry, and later botany, was his hobby. At the age of 22, Darwin was invited to join the scientific expedition on the Beagle. During its five-year voyage, the Beagle followed almost the same route as Cook's Endeavour sixty years earlier. Darwin's observations on that voyage led him to write his famous book On the Origin of Species¹.
 
        It was Darwin's visit on the Beagle to the Galapagos Isles² that gave him the key to his new theory. Darwin soon realised that the wildlife of the Galapagos Isles was very curious and deserved³ special attention. Most of the life forms could be found nowhere else. There were even differences between the species of the different islands; yet all showed a clear. relationship with those of America, though separated from that continent by about 600 miles. Darwin counted 225 flowering plants, of which he collected and brought home 193. Of these, 100 were new species which are only found in the Galapagos islands. Altogether the group of islands formed a little world within itself.
 
        Darwin first understood the development of different plant species from developments in bird species that he observed in Galapagos. He found 13 kinds of finches, related⁴ to each other in the structure of their beaks⁵, tails, shape of body and colour of their feathers. The most curious fact was the differences in the size of the beaks. This could only be explained by the differences in habitat and source of food. The birds with broad beaks would eat hard seeds, while the birds with smaller beaks would eat soft seeds or insects. Back home, in England, Darwin realised that differences in habitat could lead to different species in birds as well as in plants. He had found the key to explaining differences between species.
 
       During the 1840s and 1850s Gregor Mendel conducted his experiments with flowers and peas. Mendel's attraction to research was based on his love of nature. Although his experiments were designed to support the ideas concerning⁶ the influence of environment upon plants, he found that many characteristics were passed on from one generation to the next, without influence by the environment. His research gave birth to the science of genetics.
 
       As a result of Darwin and Mendel's research, scientists of the nineteenth century formed the belief that the influence of the environment was behind the development of new species. Still, both Darwin and Mendel observed that within species, different varieties could occur. Darwin studied many varieties of garden roses. It would take a next generation of scientists to bring the importance of the environment on species back in view.
 
       In 1922, G6te Turesson found evidence for the existence of stable varieties within species in nature. He showed that differences between plants of one species occurred as a result of the environmental conditions in their habitat. He made his discoveries by studying a wild plant found on the Swedish west coast. When growing on rocks, the plant grows to a bush, having broad leaves and large flowers. However, when growing on sand, the plant grows close to the ground, having narrow leaves and small flowers. If plants from one habitat were moved to the other type. of habitat, they changed their appearance and adapted to the new environment.
 
       The research by Darwin, Mendel and Turesson shows that both genetics and the environment are important to plants. For the improvement⁷ of crops Mendel's genetics were long considered the most important. However, Turesson's findings⁸ show that habitat, such as soil conditions, is of equal importance to the output⁹ of crops.

1 species   

n.物种，种群

参考例句：

• Are we the only thinking species in the whole of creation?我们是万物中惟一有思想的物种吗？
• This species of bird now exists only in Africa.这种鸟现在只存在于非洲。

2 isles   

岛( isle的名词复数 )

参考例句：

• the geology of the British Isles 不列颠群岛的地质
• The boat left for the isles. 小船驶向那些小岛。

3 deserved   

adj.应得的，当然的v.应受，应得，值得( deserve的过去式和过去分词 )；应受报答；应得报酬；应得赔偿

参考例句：

• Some of you deserved to succeed and others only scraped through. 你们当中有些人成功是理所当然，而有些人只是勉强及格。 来自《简明英汉词典》
• Don't glare at me like that, you deserved the scolding. 不要那么瞪着我，你本该受到训斥的。 来自《简明英汉词典》

4 related   

adj.有关系的，有关联的，叙述的，讲述的

参考例句：

• I am not related to him in any way.我和他无任何关系。
• We spent days going through all related reference material.我们花了好多天功夫查阅所有有关的参考资料。

5 beaks   

n.鸟嘴( beak的名词复数 )；鹰钩嘴；尖鼻子；掌权者

参考例句：

• Baby cockatoos will have black eyes and soft, almost flexible beaks. 雏鸟凤头鹦鹉黑色的眼睛是柔和的，嘴几乎是灵活的。 来自互联网
• Squid beaks are often found in the stomachs of sperm whales. 经常能在抹香鲸的胃里发现鱿鱼的嘴。 来自互联网

6 concerning   

prep.关于，论及

参考例句：

• What do you know concerning this?关于这事你知道些什么？
• Some senior students wrote in asking for information concerning postgraduate studies.一些四年级学生写信询问有关研究生课程的信息。

7 improvement   

n.改进，增进；改进之处，改善的地方

参考例句：

• The doctor noticed a gradual improvement in his patient.医生注意到病人在逐渐恢复健康。
• I can detect signs of improvement in your thinking.我可以察觉出你思考问题方面的进步。

8 findings   

n.发现物( finding的名词复数 )；调查（或研究）的结果；（陪审团的）裁决

参考例句：

• It behoves us to study these findings carefully. 我们理应认真研究这些发现。
• Their findings have been widely disseminated . 他们的研究成果已经广为传播。

9 output   

n.产量，输出，输出功率，输出端；vt.输出(信息等)

参考例句：

• Grain output reached a new high in the three years.谷物产量达到三年中最高水平。
• The chart showed us the global output of a factory.这张图表展示了一个工厂的总产量。