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
61
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
What can be inferred from Paragraph 6 about the pheromones of female snakes?
选项
A、They are produced year round.
B、They are species specific.
C、They are only detectable by male snakes.
D、They are the strongest chemical odors.
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/rAyO777K
0
托福(TOEFL)
相关试题推荐
DothefollowingstatementsagreewiththeviewsofthewriterinReadingPassage3?Inboxes33-37onyouranswersheet,write
Matchinginformationandfeature.OutofAfrica:solarenergyfromSaharaVivienneWaltreportsonhowtheSaharaDesertcouldo
CompanyInnovationA.InashabbyofficeindowntownManhattan,agroupof30AI(artificialintelligence)programmersfrom
CompanyInnovationA.InashabbyofficeindowntownManhattan,agroupof30AI(artificialintelligence)programmersfrom
CompanyInnovationA.InashabbyofficeindowntownManhattan,agroupof30AI(artificialintelligence)programmersfrom
SECTION3Questions21-30Questions21Whichthreeguestsareontheradioprogramme?Writethecorrectletteronyouranswer
Whatpercentageofthestudentsaremature?New-townisEngland’s______city.
Whatpercentageofthestudentsaremature?Whatpercentageofthestudentsarefromabroad?
Theprofessorsaysthatsuperhighways______.Thestudentbelievesthathighways______.
HowlonghasJackhadhisownbusiness?WhatdoesAhmedfetchbeforetalkingtoJackindetail?
随机试题
计算简答题:根据所给材料回答问题。(需计算后回答的问题,须列出算式;每个问题计算过程中的小数均保留实际位数,计算结果有小数的,小数保留2位。)张某、李某经商议共同创作一部作品《侵权案例分析》,两人约定写作分工,张某负责案情的改写,李某负责案例分析
佳节刚过,南方某宾馆的迎宾楼,失去了往日的喧哗,寂静的大厅半天也看不到一位来宾的身影。客房部管理员A紧锁眉头,考虑节后的工作安排。突然她喜上眉头,拿着电话与管理员B通话:目前客源少,何不趁此机会安排员工休息。管理员B说:“刚刚休息了7天,再连着休息,会不会
慢性肺源性心脏病时,肺的病理变化可以有
下列关于急性肾小球肾炎并发高血压脑病的治疗,说法错误的是
男,5岁。发热1天。前两天每天腹泻14~16次,为黏液性脓血便,腹痛伴里急后重,病前吃过未洗的黄瓜,粪便常规检查:黏液便,红白细胞满视野。诊断为细菌性痢疾,其类型属于
密闭作业的作业空间是指()的有限空间。
设计概算的三级概算是指()。
硬盘在使用过程中一定要防止()。
根据以下情境材料,回答问题。某日傍晚6时左右,民警庄某在卡点发现要追捕的抢劫犯罪嫌疑人邢某驾摩托车驶来,喝令邢某停车。听到喊声,邢某不但没有停车,反而加大油门继续行驶。庄某紧追不放,到镇里一个菜市场处,由于人群聚集,邢某停车欲逃,庄某拔出手枪,经警告无效
Language,likefood,isabasichumanneedwithoutwhichachildatacriticalperiodoflifemightbe______anddamaged.
最新回复
(
0
)