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
Naturalists and casual observers alike have been struck by the special relationship between squirrels and acorns (th
Naturalists and casual observers alike have been struck by the special relationship between squirrels and acorns (th
admin
2004-12-30
58
问题
Naturalists and casual observers alike have been struck by the special relationship
between squirrels and acorns (the seeds of oak trees). Ecologists, though, cannot observe
These energetic mammals scurrying up and down oak trees and eating and burying acorns
without wondering about their complex relationship with trees. Are squirrels dispersers
(5) and planters of oak forests or pesky seed predators? The answer is not simple. Squirrels
may devour many acorns, but by storing and failing to recover up to 74 percent of them
(as they do when seeds are abundant), these arboreal o\rodents can also aid regeneration
and dispersal of the oaks.
Their destructive powers are well documented. According to one report, squirrels
(10) destroyed tens of thousands of fallen acorns from an oak stand on the University of
Indiana campus. A professor there estimated that each of the large while oaks had.
Produced between two and eight thousand acorns, but within weeks of seed maturity,
Hardly an intact acorn could be found among the fallen leaves.
Deer, turkey, wild pigs, and bears also feed heavily on acorns, but do not store them,
(15) And are therefore of no benefit to the trees. Flying squirrels, chipmunks, and mice are
Also unlikely to promote tree dispersal---whose behavior of caching (hiding) acorns below
The leaf litter often promotes successful germination of acorns---and perhaps blue jays,
Important long-distance dispersers, seem to help oaks spread and reproduce.
Among squirrels, though, there is a particularly puzzling behavior pattern. Squirrels
(20) pry off the caps of acorns, bite through the shells to get at the nutritious inner kernels,
and then discard them half-eaten. The ground under towing oaks is often littered with
thousands of half-eaten acorns, each one only bitten from the top. Why would any animal
waste so much time and energy and risk exposure to such predators as red-tail hawks only
to leave a large part of each acorn uneaten? While research is not conclusive at this point,
(25) one thing that is certain is that squirrels do hide some of the uneaten portions, and these
acorn halves, many of which contain the seeds, may later germinate.
选项
A、The ecology of oak trees
B、Factors that determine the feeding habits of Squirrels
C、Various species of animals that promote the dispersal of tree seeds
D、The relationship between squirrels and oak trees
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/KK8O777K
0
托福(TOEFL)
相关试题推荐
ReadthetextbelowandanswerQuestions8-14.*Onlyonediscountmayapplytoeachfare.CHANGESANDREFUNDSTicketsmaybere
ReadthetextbelowandanswerQuestions7-14.INTERCITYSleeperbetweenLondonandScotlandMostticketsmayb
DothefollowingstatementsagreewiththeinformationgiveninReadingPassage3?Inboxes37-40onyouranswersheet,writeTR
Accordingtothewriter,currenttrendsintheheritageindustry
Completethesummarybelow.ChooseONEWORDONLYfromthepassageforeachanswer.Writeyouranswersinboxes24-26onyourans
Youshouldspendabout20minutesonQuestions14-26whicharebasedonReadingPassage2below.Youngchild
Youshouldspendabout20minutesonQuestions14-26whicharebasedonReadingPassage2below.Youngchild
Youshouldspendabout20minutesonQuestions27-40whicharebasedonReadingPassage3below.AmateurNaturalistsFromthere
Labelthemapbelow.Writethecorrectletter,A-H,nexttoquestions16-20.MedicalRecordsOffice
PRIMERECRUITMENTEmploymentrecordExampleSurname:LamertonEmail:【L1】___________________@worldnet.comNationality:【L2】____
随机试题
妊娠期高血压疾病孕妇,于妊娠晚期出现腹痛伴阴道出血,最可能的诊断是下列何项
男,50岁。颈增粗20年,近一年消瘦l0kg,并有心悸。体检发现双侧甲状腺多个结节。基础代谢率+31%,2小时内甲状腺摄碘29%。最可能的诊断是
2011年2月,下列人员向所在单位提出订立无固定期限劳动合同,所在单位不同意,其中不满足订立无固定期限劳动合同法定条件的是()。
我国北方唯一以捕鱼为主要生产方式和使用狗拉雪橇的民族是()。
某社区中有许多心脏病患者,社会工作者王刚组织这些患者成立了自助小组,让组员们互相交流经验、释放情绪,并请来权威专家为大家讲解应对心脏病突发的办法,及平时生活饮食上应注意的问题。在此过程中,王刚应用了()等技巧。
《竹林七贤图》最初的材质是()。
【2015年淄博市真题】个体通过理解事物之间的关系、结构和性质而突然察觉到问题解决的办法,这种学习是()。
求下列极限:
在考生文件夹下打开文档WD1O.DOC.其内容如下:【文档开始】专业方向必修课评定成绩注:由于2003级还未开课,大部分学生都选择不确定,因而该课程的评定成绩有特殊性。专业方向必修课的评定结果比较令人满意,这说明学院目前在这一部分的课程设置比较合理
TheAmericanWay:FreedomTheheartoftheAmericancalendarisJuly4Americanshavecelebrat-ed-thisdateas"Independence
最新回复
(
0
)