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
29
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、Its geography is similar to Brazil’ s.
B、Their instinct leads them to the place they were hatched.
C、There are other species of turtles located there.
D、Its climate is milder than Brazil’ s.
答案
B
解析
细节题。根据the instinct that drives green turtles to always return to the beach where they were hatched.可知,一种假设是绿乌龟们出于本性,返回到自己孵化出来的地方。因此,正确答案是B。
转载请注明原文地址:https://tihaiku.com/zcyy/2913504.html
相关试题推荐
[originaltext][22-1]ShortlyafterhetookovertheReader’sDigestAssociation
[originaltext][22-1]ShortlyafterhetookovertheReader’sDigestAssociation
[originaltext]Goodmorning,ladiesandgentlemen,andwelcometothethirdino
[originaltext]Goodmorning,ladiesandgentlemen,andwelcometothethirdino
[originaltext]Governments,privategroupsandindividualsspendbillionsofdol
[originaltext]Governments,privategroupsandindividualsspendbillionsofdol
[originaltext]Governments,privategroupsandindividualsspendbillionsofdol
[originaltext]RonaldandLouismarriedfortwodecadesconsiderthemselvesa
[originaltext][19-1]Thethin,extremelysharpneedlesdidn’thurtatallgo
[originaltext][22-1]ShortlyafterhetookovertheReader’sDigestAssociation
随机试题
Thomasaskedthathe______allowedtotakethecoursethissemester.A、couldbe
Itmaycomeasasurprisetomanyanexhaustedmotherorfather—butthinking
一些企业已经用微机和网络取代了大型计算机,因为较小的计算机能以较低的成本完成同样
某煤矿为增值税一般纳税人,2019年4月发生下列业务: (1)开采原煤4000
16591
关于听力的叙述,的是 A.人耳能感受的振动频率在16?20000Hz B.
下列各句中,没有语病的一句是( )。A.受“非典”影响,这个厂的利税较去年下降
个人质押贷款还款方式包括( )。A.等额本息还款法 B.按月还息、分次任意还
一住店客人未付房钱即想离开旅馆去车站。旅馆服务员揪住他不让走,并打报警电话。客人
患者,女,69岁。戴全口义齿后感到牙槽嵴普遍疼痛,面部肌肉酸痛,上腭有烧灼感,每
最新回复
(
0
)