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
Species interdependence in nature confers many benefits on the species involved, but it can also become a point of weakness when
Species interdependence in nature confers many benefits on the species involved, but it can also become a point of weakness when
admin
2011-02-10
64
问题
Species interdependence in nature confers many benefits on the species involved, but it can also become a point of weakness when one species involved in the relationship is affected by a catastrophe. Thus, flowering plant species dependent on insect pollination, as opposed to self- pollination or wind pollination, could be endangered when the population of insect-pollinators is depleted by the use of pesticides.
In the forests of New Brunswick, for example, various pesticides have been sprayed in the past 25 years in efforts to control the spruce budworm, an economically significant pest. Scientists have now investigated the effects of the spraying of Matacil, one of the anti-budworm agents that is least toxic to insect-pollinators. They studied Matacil’s effects on insect mortality in a wide variety of wild insect species and on plant fecundity, expressed as the percentage of the total flowers on an individual plant that actually developed fruit and bore seeds. They found that the most pronounced mortality after the spraying of Matacil occurred among the smaller bees and one family of flies, insects that were all important pollinators of numerous species of plants growing beneath the tree canopy of forests. The fecundity of plants in one common indigenous species, the red-osier dogwood, was significantly reduced in the sprayed areas as compared to that of plants in control plots where Matacil was not sprayed. This species is highly dependent on the insect-pollinators most vulnerable to Matacil. The creeping dogwood, a species similar to the red-osier dogwood, but which is pollinated by large bees, such as bumblebees, showed no significant decline in fecundity. Since large bees are not affected by the spraying of Matacil, these results add weight to the argument that spraying where the pollinators are sensitive to the pesticide used decreases plant fecundity.
The question of whether the decrease in plant fecundity caused by the spraying of pesticides actually causes a decline in the overall population of flowering plant species still remains unanswered. Plant species dependent solely on seeds for survival or dispersal are obviously more vulnerable to any decrease in plant fecundity that occurs, whatever its cause. If, on the other hand, vegetative growth and dispersal (by means of shoots or runners) are available as alternative reproductive strategies for a species, then decreases in plant fecundity may be of little consequence. The fecundity effects described here are likely to have the most profound impact on plant species with all four of the following characteristics, a short life span, a narrow geographic range, an incapacity for vegetative propagation, and a dependence on a small number of insect- pollinator species. Perhaps we should give special attention to the conservation of such plant species since they lack key factors in their defenses against the environmental disruption caused by pesticide use.
According to the author, a flowering plant species whose fecundity has declined due to pesticide spraying may not experience an overall population decline if the plant species can do which of the following? ______
选项
A、Reproduce itself by means of shoots and runners.
B、Survive to the end of the growing season.
C、Survive in harsh climates.
D、Respond to the fecundity decline by producing more flowers.
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/K8cO777K
本试题收录于:
NAETI中级口译笔试题库外语翻译证书(NAETI)分类
0
NAETI中级口译笔试
外语翻译证书(NAETI)
相关试题推荐
Wehavesentanordersliptoallthatwehavereasontobelieveareinterestedinourbooks.
TheancientJewishpeopleregardedthemselvesasthesaltoftheearth,thechosenfewbyGodtoruletheworld.
Seekingtobuildsupportamongblackfamiliesforitseducationreformlaw,theBushadministrationpaidaprominentblackpundi
Inthepopularmind,theInternetistherealizationoftheglobalvillage,wheretheflowofinformationandideasisunimpeded
TheoriesonWhyWeLikeOtherPeopleInordertofigureoutthereasonswhywefallinlikeandwhywefallinlovewithpeop
Thepresidentofthecorporationdemandedthatallimportantbusinessdocumentsbephotocopiedincaseofacomputerdisaster.
MemoryBrainsaredifferentfromcomputers,buttheanalogycanbehelpful.LikethePConyourdesk,yourmindisequippedw
FoulShotsNowandthenIcanstillseetheirfaces,nickeringandlaughing,theireyesmockingme.AnditbothersmethatI
Ishouldcometothespotsoon,butthatIhavebeenmuchengagedwithsomeformalities.
WhichofthefollowingmayNOThappenthisTuesday?
随机试题
从宽泛的角度认识谈判者利益,要区分___________、___________、___________。
载脂蛋白AI是下列哪种酶的激活剂?
下列有关体表感染的描述,错误的是
煤焦油可致皮肤癌。研究发现,经煤焦油涂抹的皮肤如再接触佛波酯,肿瘤的发生率增加,潜伏期缩短。据此实验,佛波酯应属
患者,女,20岁,未婚。近4个月月经提前8~10天,量多、色淡、质稀,神疲肢倦,小腹空坠,舌淡,脉缓弱。诊为月经先期,其证候是
钢丝绳的规格较多,起重工程常用的为()。
甲发现一只羊在自家的田里吃麦苗,便将此羊牵回家,并精心喂养,一周后,乙发现自家丢失的羊在甲家的羊圈里,便向甲索要羊。甲同意乙将羊牵回,但提出了一些请求,甲的下列请求中,能够获得法律支持的有()。
该企业可享受到的税收优惠措施有( )。2002年可获得的退税额为( )万元。
“经济上落后的国家在哲学上仍然能演奏第一提琴”,这是因为社会意识的存在和发展具有相对的独立性。社会意识的相对独立性表现为
Cansocietiesberichandgreen?[A]"Ifoureconomiesaretoflourish,ifglobalpovertyistobeeliminatedandifthewell-bei
最新回复
(
0
)