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
The Snake’s Forked Tongue 1. One of the most intriguing physical characteristics of snakes is their forked tongues. While thi
The Snake’s Forked Tongue 1. One of the most intriguing physical characteristics of snakes is their forked tongues. While thi
admin
2012-01-14
47
问题
The Snake’s Forked Tongue
1. One of the most intriguing physical characteristics of snakes is their forked tongues. While this trait is also shared by some types of lizards, all snake species exhibit split tongues, which usually have a more
pronounced
fork than those of lizards. Any observer of snakes has no doubt noticed that they often stick their tongues out of their mouths, flick them up and down in the air, and then retract them. In fact, due to a slight indentation in the upper jaw, many species can protrude their tongues without even opening their mouths.
2. The explanation for this behavior remained unknown for centuries, giving rise to many
folk superstitions.
For example, the forked tongue has become synonymous with deceit, from the idea that two separate tongues would enable a creature to voice two contrasting ideas at the same time. Another popular misconception is that snakes sting other animals with their tongues. Recently, though, scientists uncovered the truth about the forked tongue, and its actual use is much less sinister.
3. Snakes differ greatly from humans on a sensory level. On the one hand, their eyesight is poor and they lack outer ears so they cannot hear with much volume or clarity, but, on the other, some have the ability to "see" and hunt in the dark by sensing the body heat of their prey.
In addition, snakes have a method of smelling that is peculiar in that it is actually performed by the tongue rather than by the nostrils and nasal cavities, which in fact undertake other functions, such as breathing.
When a snake flicks its tongue around in the air, it is actually
snaring
chemical particles, which can be thought of as odors. Next, the snake brings its tongue back in and places it against the roof of its mouth, where there are two small openings that correspond to the two tips of the forked tongue.
These
make up the snake’s Jacobson’s organ, a kind of chemoreceptor that analyzes the chemical odors on the tongue and sends this information to the snake’s brain.
4. This technique for "smelling" the surrounding environment is truly unique, but even more amazing is the reason why the snake’s tongue is forked. By spreading the tips apart when the tongue is flicked out, each samples chemical particles from a slightly different position in the air and brings them back to the Jacobson’s organ.The organ then determines which tip was exposed to a larger amount of the particles in question, and this data tells the snake where the source of the odor can be found. In other words, if the tongue’s right tip contains more of the particles, such as those of an animal’s chemical odor, the snake knows that to find the animal it must travel to the right, not to the left.
5. Obviously, the ability of snakes to pursue scents in this fashion is very useful in hunting,A It has been proven to be quite accurate, allowing them to pick up the trail of rodents and other prey even though the animal itself may be a great distance away.B Similarly, if the odor the snake
perceives
belongs to a predator, it is able to adjust its course to steer clear of the danger, C Another suggested use of snakes’ sense of smell is that it aids them in ascertaining the locations of communal dens*, where snakes reside in groups during the winter months.D
6. However, scientists who have studied the chemoreception process in snakes believe its most vital role is in the detection of mates. Because most snakes lead solitary lives for much of the year, the capability of males to track down females during the mating season is essential for the survival of snake species. A male does this by sampling the air for the pheromones of a female. The chemical odor given off by the female gives the male all the information he needs, including whether she is of the same species, whether she is ready to mate, and in which direction she is traveling. Without the olfactory use of their tongues, it would be much harder for snakes to reproduce.
den* the home of certain types of wild animals such as lions or foxes
According to Paragraph 4, what is the function of the Jacobson’s organ in snakes?
选项
A、To assist in the search for chemical particles in the air.
B、To enable the tongue’s fork to be spread more widely.
C、To utilize the snake’s trained sense of direction.
D、To compare the sensory input of the two tongue tips.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/0AyO777K
0
托福(TOEFL)
相关试题推荐
DothefollowingstatementsagreewiththeviewsofthewriterinReadingPassage3?Inboxes33-37onyouranswersheet,write
DothefollowingstatementsagreewiththeinformationgiveninReadingPassage2?Inboxes16-20onyouranswersheet,writeT
SECTION3Questions21-30Questions21Whichthreeguestsareontheradioprogramme?Writethecorrectletteronyouranswer
AccordingtoMrSingh,onwhichthingdomanypeoplemakesuperficialobservations?AccordingtoMrSingh,whatgreatadvantage
Whatpercentageofthestudentsaremature?Howarethesuburbsdescribed?
Betweenwhattimesistheroadtrafficlightest?doublethicknessplasterboard
TheprofessoralreadyknowssomethingaboutClarefromher______.
Whichgroupgavethefollowingadvice?TickColumnAifitwasmainlywomen.TickColumnBifitwasmainlymen.TickColumnCi
Whatadvantagedoesthespeakermentionforeachofthefollowingphysicalactivities?ChooseSIXanswersfromtheboxandwrite
随机试题
Whatproblemdoesthespeakermention?
下列对逆转录的叙述错误的是
视物变形不见于
国际债券的发行人主要有()。Ⅰ.各国政府、政府所属机构Ⅱ.银行或其他金融机构Ⅲ.自然人Ⅳ.工商企业
公安机关因查处经济违法犯罪案件,需要向银行查询企业的存款资料时,应当出具()公安局签发的“协助查询存款通知书”。
采用普通股筹资,由于新股东分享公司未发行新股前积累的盈余,会降低普通股的每股净收益,从而可能引起股价的( )。
比较西安与成都,你会发现它们在某些方面相似。(compare…with;and;insomeways)
2011年5月1日,江北县甲公司在江南县的订货会上向江中县乙公司订购10套设备。甲公司于5月3日签字盖章后将合同书邮寄给乙公司,乙公司于5月5日签收并于当日签字盖章后邮寄给甲公司,甲公司于5月8日签收合同书,双方约定:设备总价款200万元;交货时间为10月
如下所示的图为UML的_______(1),用于展示某汽车导航系统中_______(2)。Mapping对象获取汽车当前位置(GPSLocation)的消息为_______(3)。(3)
Althoughhehasbecomerich,heisstillvery______ofhismoney.
最新回复
(
0
)