首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A、Teach their young how to swim. B、Mate and lay eggs. C、Hide from predators. D、Eat different kinds of fish. BWhat?do?green?turtl
A、Teach their young how to swim. B、Mate and lay eggs. C、Hide from predators. D、Eat different kinds of fish. BWhat?do?green?turtl
admin
2013-04-25
42
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 allowe 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.
选项
A、Teach their young how to swim.
B、Mate and lay eggs.
C、Hide from predators.
D、Eat different kinds of fish.
答案
B
解析
What?do?green?turtles?do?when?they?get?to?Ascension?Island?
转载请注明原文地址:https://kaotiyun.com/show/tSyO777K
0
托福(TOEFL)
相关试题推荐
AccordingtoMrSingh,onwhichthingdomanypeoplemakesuperficialobservations?AccordingtoMrSingh,whatareyoungIndia
SECTION4Questions31-40Questions31-33Completethefollowingsentencesaccordingtotheinformationgivenbythetutor.Use
SECTION4Questions31-40Questions31-35Completethenotesbelow.WriteNOMORETHANTHREEWORDSorANUMBERforeachanswer.
Betweenwhattimesistheroadtrafficlightest?Whichdayoftheweekhastheleasttraffic?
SECTION3Questions21-30Questions21-23CompletethefollowingsentencesusingNOMORETHANTHREEWORDSforeachgap.
SECTION4Questions31-40Questions31-33CompletethefollowingnotesondifferencesyoumightnoticewhenyougohomeusingNO
Completethefollowingsentences.UseNOMORETHANTHREEWORDSforeachanswer.Thespeakeridentifiesthefollowingtwo
Whichattitudeisassociatedwiththefollowingpeopleduringtheconversation?ChooseSIXanswersfromtheboxandwritetheco
A、StudypaintingsbyotherartistsB、Gotoherfather’sartexhibitC、ShowtheinstructorhissketchesD、Changethecolorofthe
ForestryForestFireListenagaintopartofthetalk.Thenanswerthequestion.Whatdoestheinstructormeanbythisstatemen
随机试题
某无形资产,法律规定受益期为10年,企业合同中规定有益年限为9年,则该无形资产的有效期限为
男,67岁。戴全口义齿数周,由于疼痛来院复诊。检查:全口义齿固位良好,患者无法准确指出疼痛部位,口腔黏膜未见明显压痛点。本例最有可能造成的原因是
患者,女性,48岁,有口腔黏膜粗涩感,进食刺激性食物感疼痛半年,检查发现其舌背左右各一黄豆大小白色病损,浅淡,表面乳头消失,质软。双颊自口角至颊脂垫尖处广泛白色角化网纹,基底充血发红。双舌缘舌腹也可见类似病损。询问病史及临床检查时应当注意以下几点,除了
采用家兔试验测定C3垂熔玻璃滤器
九分散中马钱子粉与麻黄等,采用下列哪种方法与其余药粉混匀,制得散剂( )。
土地权属变化的主要因素中,不包括()。
下列关于城乡规划管理表述正确的是()。
在证券经纪业务中,客户回访应当留痕,相关资料应当保存不少于()年。
去年建成今年销售的房地产和今年建成已销售的房地产均计入今年的GDP。()
国家实行()登记发证制度。
最新回复
(
0
)