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
2024-04-09
42
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/3547174.html
相关试题推荐
[originaltext]Thosewhousesolarenergyhelpussaveourpreciousfuel.As
[originaltext]Thosewhousesolarenergyhelpussaveourpreciousfuel.As
[originaltext]Formostpeople,readinganewspaperhasbecomeahabitpasse
[originaltext]Theadvantagesanddisadvantagesofalargepopulationhavel
[originaltext]Theadvantagesanddisadvantagesofalargepopulationhavel
[originaltext]W:Honey,couldyoucomehereforasecond.Weneedtotalk.Myp
[originaltext]W:Honey,couldyoucomehereforasecond.Weneedtotalk.Myp
[originaltext]W:Iwasworkingonapaperaboutthedifferencesbetweenwomena
[originaltext]W:Iwasworkingonapaperaboutthedifferencesbetweenwomena
[originaltext]W:Areyougoingtothedinnerforyoungteacherstomorrownight?
随机试题
[originaltext]Iwillletyouknowthatthere’sabigdifferencebetweenund
GreenhouseEffectⅠ.Introduction
在社会主义市场经济条件下,仍然要提倡集体主义,反对()A.个人利益 B.极端
某弱酸性药物的pKa是3.4,则其在血浆中的解离百分率约为()。A.99.9
站立训练适应证是A.下肢骨折未愈合者,骨骼运动系统的病变或损伤影响行走功能的患者
我国( )负责全国风景名胜区的监督管理工作。A.国家旅游行政管理部门 B.国
欲表示某地区某年各种死因的构成比,可绘制A.线图 B.直方图 C.百分条图或
患者男性,68岁。二尖瓣狭窄病史30年,1周前感冒后出现呼吸困难,紫绀,咳粉红色
A.发汗、解热、抗炎 B.增加或调节免疫 C.收敛、止泻、止血 D.抗菌、
处置固定资产、无形资产和其他长期资产收回的现金净额应计入企业现金量表中()产生
最新回复
(
0
)