首页
登录
职称英语
Zoology Animal Defenses[img]2012q1/ct_etoefm_etoeflistz_0219_20121[/img] [br] Wh
Zoology Animal Defenses[img]2012q1/ct_etoefm_etoeflistz_0219_20121[/img] [br] Wh
游客
2024-01-04
28
管理
问题
Zoology Animal Defenses
[br] What does the professor mean when she says this:
One of the most important relationships between different animal species is predation—the predator-prey interaction, in which a predator eats a prey. Predator species have several adaptations that help them catch prey species. Prey species have adaptations, too—physical and behavioral adaptations that enable them to elude predators and avoid being eaten. These defensive adaptations evolved in prey species through repeated encounters with predators over evolutionary time.
Some animal defenses are passive, such as hiding. Some defenses are active, such as escaping. Fleeing—running away—is the most direct anti-predator response, but it requires the animal to expend a lot of energy. A rabbit uses up a lot of energy running away from a lynx. Many animals avoid expending too much energy by escaping into a shelter.
Several prey species have some sort of vocalization—an alarm call—to announce the presence of a predator. The alarm call often triggers a behavioral defense called mobbing. During mobbing, the prey turns the tables and attacks the predator. For example, when a chickadee spots a threat—say, an owl—it calls out the alarm. The chickadee starts scolding the owl, sometimes actually striking it from behind. Birds of other species may fly in to investigate, and often participate in the mobbing. The other birds chase, dive-bomb, or surround the owl, usually vocalizing loudly. Their intent is to encourage the "enemy" to move on to another area.
Some animals rely on defensive coloration. A well-known example of defensive coloration is camouflage, which makes prey difficult to spot against a background of similar color. All a camouflaged animal has to do is remain still to avoid being seen. Thus, camouflage is probably the most effective passive defense. Incidentally, some predators also use camouflage, especially predators who lie in wait for prey and have to blend into their environment.
Moths that camouflage themselves to match a leaf stand a good chance of not being seen by moth-eating birds, unless, of course, the moths become so populous that a bird is likely to come across one by accident. Once the bird learns the moth’s identity, it has a search image for it, and the moth’s disguise is useless. Looking like a leaf is then no advantage because the bird will start pecking at leaves in the hope that they are moths, and it will keep doing it as long as a sufficient number do turn out to be moths.
Another animal defense is the use of chemical weapons. We’re all familiar with the chemical weapon of the skunk. Some animals—like poisonous toads and flogs—can synthesize toxins that attack the nervous system of predators. Other animals acquire chemical defenses passively. For example, some caterpillars acquire poison from the plants they eat. Then, when a bird eats the caterpillar, the bird quickly vomits. After that, the bird will avoid eating that kind of caterpillar. Some birds can remember bad-tasting meals a year later.
Another defensive adaptation is warning coloration. Animals with effective chemical defenses are often brightly colored, and there is evidence that predators are more cautious in dealing with bright color patterns in potential prey. This is probably because a lot of poisonous or bad-tasting animals are colored brightly, with black and yellow, or black and red stripes.
Warning coloration quickly trains predators to avoid eating these brightly-colored animals. Some birds have an instinctive tendency to avoid eating insects with warning coloration. For example, young warblers leave wasps alone because the birds recognize the danger in the black and yellow stripes of the wasp. However, warning coloration is not an absolute defense, as there is also evidence showing that many birds occasionally feed on bees and wasps, perhaps after learning to cope with their chemical defenses.
选项
A、Some birds have discovered that brightly-colored insects taste good.
B、Some birds have chemical defenses similar to those of insects.
C、Some birds appear able to manage the poison of bees and wasps.
D、Some birds may have forgotten the meaning of bright coloration.
答案
C
解析
What does the professor mean when she says this:
"However, warning coloration is not an absolute defense, as there is also evidence showing that many birds occasionally feed on bees and wasps, perhaps after learning to cope with their chemical defenses."
The professor means that some birds appear able to manage the poison of bees and wasps. Many birds eat bees and wasps, perhaps after learning to cope with their chemical defenses, which suggests that birds may develop ways to counteract the insects’ chemical weapons. (2.4)
转载请注明原文地址:https://tihaiku.com/zcyy/3333964.html
相关试题推荐
ENDANGEREDSPECIESAlthoughwecannotdoanythingabouttheplantsandanimalst
ENDANGEREDSPECIESAlthoughwecannotdoanythingabouttheplantsandanimalst
ENDANGEREDSPECIESAlthoughwecannotdoanythingabouttheplantsandanimalst
ENDANGEREDSPECIESAlthoughwecannotdoanythingabouttheplantsandanimalst
ENDANGEREDSPECIESAlthoughwecannotdoanythingabouttheplantsandanimalst
ENDANGEREDSPECIESAlthoughwecannotdoanythingabouttheplantsandanimalst
ENDANGEREDSPECIESAlthoughwecannotdoanythingabouttheplantsandanimalst
NarratorListentoalectureintheliteratureclass.[img]2011q1/ct_etoefm_
NarratorListentoalectureintheliteratureclass.[img]2011q1/ct_etoefm_
NarratorListentoalectureintheliteratureclass.[img]2011q1/ct_etoefm_
随机试题
Arewereadyforthelibraryofthefuture?A)Librarianstodaywilltel
Anewscholarlystudydocumentingthepoorhealthofsouthernmilitaryrecrui
患者,男性,71岁,稳定型心绞痛病史3年,近2周来心绞痛次数增多,血
封闭式基金一般至少()披露一次资产净值和份额净值。A.每月 B.每周 C.每
(2017年真题)某县工商局科员李某因旷工被给予警告处分。关于李某的处分,下列哪
组织拟订并实施长期护理保险制度改革方案的部门是A.人力资源和社会保障部门 B.
某地区农户开办了一个采摘园,让人们可以亲自种植、养护、采摘等,这种农业发展模式属
由于债务资本成本率一般低于股权资本成本率,因此,公司的债务资本越多,债务资本比例
下列筹资方式中,属于商业信用筹资方式的是()。A.短期借款 B.融资租赁
食品生产企业在开工前,必须向质量监督管理部门申请获得()。A.餐饮服务许可
最新回复
(
0
)