首页
登录
职称英语
[originaltext] I’ ve mentioned how DNA have solved many mysteries in biology.
[originaltext] I’ ve mentioned how DNA have solved many mysteries in biology.
游客
2023-08-13
41
管理
问题
I’ ve mentioned how DNA have solved many mysteries in biology. And today I want to talk about how it might relate to hypothesis about the travels of the green turtle. Every winter some green turtles make a 2000 km journey from Brazil to Ascension Island in the middle of Atlantic, where they mate and lay eggs. But the question is why do they travel so far to lay their eggs? One researcher hypothesized that there are two parts to the explanation. One is natal homing, the instinct that drives green turtles to always return to the beach where they were hatched. The second part has to do with continental drift, the theory that the positions of earth continents have changed considerably overtime. Brazil and Ascension Island were once much closer together, and continental drift drove them apart. But the turtles kept on going back to the island where they hatched. However another scientist question this explanation on the ground that it would be very unlikely that conditions would allow generations of turtles over hundreds of millions of years to keep going back to the same nesting ground every single year. So, what is the connection to DNA? Well, there are groups of green turtles that nest in locations other than the Ascension Island. If green turtles always return to the place where they were hatched, then the turtles that have been going to the Ascension Island to nest would’ve been genetically isolated long enough to have DNA that was very different from the green turtles that nest else where. But when scientists examine DNA from these turtles, their DNA wasn’t that different from the DNA of the turtles that go to Ascension Island. Do you have a shock? Well, we still don’t know the answer to the question about why a certain group of turtles go to Ascension Island, but this study was a nice example of the usefulness of DNA analysis to biology.
Now listen to the following recording and answer questions 20 to 22.
20. What do green turtles do when they get to Ascension Island?
21. According to one hypothesis, why do green turtles go to Ascension Island?
22. How is DNA used in research on green turtles?
选项
A、To discover how long their ancestors lived.
B、To analyze how their appearance has evolved.
C、To find out how a disease has spread
D、To determine how closely groups of turtles are related.
答案
D
解析
细节题。根据then the turtles that have been going to the Ascension Island to nest would’ve been genetically isolated long enough to have DNA that was very different from the green turtles that nest else where.可知,有些乌龟到阿森松岛筑巢,由于地点偏远,脱离了主体,它们的DNA与其他乌龟不同了。因此,用DNA判断乌龟种族之间的远近度。因此,正确答案是D。
转载请注明原文地址:https://tihaiku.com/zcyy/2921209.html
相关试题推荐
[originaltext]W:Whenwasthelasttimeyouwentforawalkinyourlocalpark?
[originaltext]W:Whenwasthelasttimeyouwentforawalkinyourlocalpark?
[originaltext]W:Whenwasthelasttimeyouwentforawalkinyourlocalpark?
[originaltext][19]Imagineabigexplosionasyouclimbthrough3,000ft.I
[originaltext][19]Imagineabigexplosionasyouclimbthrough3,000ft.I
[originaltext]E-booksarebringingaboutaprofoundrevolutioninthewayb
[originaltext]AmericanmagicianDavidBlaineistobesuspendedinaglass
[originaltext]AmericanmagicianDavidBlaineistobesuspendedinaglass
[originaltext]W:Hello.Isthistheregistrationoffice?M:Yes.ThisisHerber
[originaltext]W:Hello.Isthistheregistrationoffice?M:Yes.ThisisHerber
随机试题
Wasitbecauseitsnowedlastnight________youdidn’tcome?A、whenB、thatC、soD、
球后麻醉时封闭睫状神经节达到镇痛作用,是由于睫状神经节含有()A.来自外
八名受访者表示6月份网购的次数为:2,2,3,2,5,1,3,6。则其6月份网购
共用题干 RelievingthePain"Exercisemaybe
制药用水不包括A:饮用水 B:注射用水 C:灭菌注射用水 D:天然矿物质水
控制图中控制限的作用是()。 A.区分偶然波动与异常波动 B.区分合格
“肺之门户”指的是A.口 B.喉 C.鼻 D.唇 E.目
紧缩性的财政政策措施主要包括()。A.增加政府支出 B.降低法定存款准备
用于工程的钢筋进场后,应按规定抽取试件进行拉伸试验,试验内容包括( )。A、抗拉
根据《水利水电工程等级划分及洪水标准》(SL252-2017),确定临时水工建筑
最新回复
(
0
)