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
2023-08-10
26
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/2913505.html
相关试题推荐
Thedesireforachievementisoneoflife’sgreatmysteries.Socialscientis
Thedesireforachievementisoneoflife’sgreatmysteries.Socialscientis
[originaltext][19]Iamhonoredtobewithyoutodayatyourcommencementf
[originaltext][19]Iamhonoredtobewithyoutodayatyourcommencementf
[originaltext][19]Iamhonoredtobewithyoutodayatyourcommencementf
[originaltext][19]Iamhonoredtobewithyoutodayatyourcommencementf
[originaltext][16]LeonardBernsteinsaidthattoachievegreatthings,you
[originaltext][16]LeonardBernsteinsaidthattoachievegreatthings,you
[originaltext]Theworld’ssmartestadolescentsinmathematicsandsciencea
[originaltext]Theworld’ssmartestadolescentsinmathematicsandsciencea
随机试题
Duringthelastfewyears,therehasbeenan【B1】______increaseinthenu
[originaltext]M:Haveyounoticedthenewdustbindownstairs,attheentranceo
在民事法律关系中,民事主体依其合法行为而形成并能够正常实现的民事法律关系是()法
设f′(lnx)=1+x,则f(x)=()。A. B. C. D.
在产品采用成本法评估时,下列各项费用中,构成在产品重置成本的有( )。A、材料
某企业生产和销售单一产品,销售单价为20元/件,变动成本率为60%。2019年固
下列关于公司型基金、合伙型基金、信托(契约)型基金的说法,错误的是()。A.只
经()以上业主委员会委员的提议,应当及时召开业主委员会会议。A:1/3 B:2
证券公司为期货公司提供中间介绍业务过程中发生重大事项的,应当在( )个工作日内
【背景资料】 某安装公司总承包氮氢压缩分厂全部机电安装工程,其中氮氢压缩机为多
最新回复
(
0
)