为什么说蜘蛛不是昆虫 那它是什么 (蜘蛛不是昆虫是什么呢英语)
为什么说蜘蛛不是昆虫 那它是什么 (蜘蛛不是昆虫是什么呢英语)
蜘蛛不具有昆虫的基本特征，所以不是昆虫。
昆虫的基本特征是体躯三段头、胸、腹，2对翅膀与6只足。而蜘蛛身体分头胸部（前体）和腹部（后体）两部分，头胸部覆以背甲和胸板，没有翅膀，头胸部有附肢6对。
蜘蛛是节肢动物，节肢动物门蛛形纲蜘蛛目所有种的通称。除南极洲以外，全世界分布。从海平面分布到海拔5,000米处。
扩展资料
生活习性
1、食性
蜘蛛多以昆虫、其他蜘蛛、多足类为食，部分蜘蛛也会以小型动物为食。
（1）化尸大法：
蜘蛛猎食时先用毒牙里的毒素麻痹猎物，分泌消化液注入猎物体内溶解猎物，再慢慢吸食，一点儿不漏吃个干净。
（2）自制保鲜袋：
蜘蛛怕光，经常对着透光和透风的地方结网。蜘蛛丝除了用来网罗猎物外，还可用来当保鲜袋，蜘蛛将吃剩的食物用网把猎物包好，留待下次食用。
（3）洁癖：
蜘蛛将吃、睡和拉的场所分得很清楚，家养的蜘蛛一般把笼边当垃圾站，在那里大小便及扔食物残渣。
（4）胃口极秀气。
2、建巢
蜘蛛在母性方面的表露甚至比猎取食物时所显示的天才更令人叹服。
它的巢是一个丝织的袋，它的卵就产在这个袋里。它这个巢要比鸟类的巢神秘，形状像一个倒置的气球，大小和鸽蛋差不多，底部宽大，顶部狭小，顶部是削平的，围着一圈扇蛤形的边。
整个看来，这是一个用几根丝支持着的蛋形的物体。
巢的顶部是凹形的，上面像盖着一个丝盖碗。它是防水的，雨水或露水都不能浸透它。
用剪刀把包在外面的这层防雨缎子剪开来，里面这层丝是很蓬松的一束。它是未来的小蜘蛛们的安乐床。小蜘蛛们在这张舒适的床上就不会受到寒冷空气的侵袭了。
3、生活方式
蜘蛛的生活方式可分为两大类。即游猎型和定居型。
游猎型者：到处游猎、捕食、居无定所、完全不结网、不挖洞、不造巢的蜘蛛。有鳞毛蛛科，拟熊蛛科和大多数的狼蛛科等。
定居型的：有的结网，有的挖穴，有的筑巢，作为固定住所。如壁钱、类石蛛等。蜘蛛似乎懂礼貌，凡营独立生活者，个体之间都保持一定间隔距离，互不侵犯。
参考资料来源：百度百科-蜘蛛 （节肢动物）
spider 读音：英 ['spaɪdə(r)] 美 ['spaɪdər]
arachnid 读音：英 [əˈræknɪd] 美 [ə'ræknɪd]
单词解析：
1、spider
释义：n. 蜘蛛；十字叉；三脚架；长柄平底锅
例句：The spider can catch insects by cobweb.
蜘蛛能用蜘蛛网抓住昆虫。
2、arachnid
释义：n.蜘蛛；蛛形纲动物；蛛形动物
例句：I've discovered several arachnid tracks outside.
我在外面发现了一连串的蜘蛛痕迹。
扩展资料：
近义词
1、tarantula
释义：n.鸟蛛，狼蛛
例句：I don't want a pet that could be dangerous, like a tarantula or rattlesnake.
我不想要一只危险的动物，比如狼蛛或响尾蛇之类的。
2、black widow
释义：n.黑寡妇（一种美洲蜘蛛）
例句：With some spiders, including the black widow, the male is much smaller than the female.
在某些蜘蛛群里例如“黑寡妇”蜘蛛雄蜘蛛的个头要比雌蜘蛛小得多。
3、araneus ventricous
释义：大腹圆蛛
例句：Analysis of Amino Acid Components of Araneus Ventricous Spider Silk
大腹圆蛛丝蛋白的氨基酸组成分析
正如许多人认为蜘蛛是昆虫，
可是它们不是，
甚至跟昆虫毫无关系
应该是这样理解！
新概念英语第四册第二课
Spare that spider
Why, you may wonder, should spiders be our friends? Because they destroy so many insects, and insects include some of the greatest enemies of the human race. Insects would make it impossible for us to live in the world; they would devour all our crops and kill our flocks and herds, if it were not for the protection we get from insect-eating animals. We owe a lot to the birds and beasts who eat insects but all of them put together kill only a fraction of the number destroyed by spiders. Moreover, unlike some of the other insect eaters, spiders never do the harm to us or our belongings.
Spiders are not insects, as many people think, nor even nearly related to them. One can tell the difference almost at a glance, for a spider always has eight legs and insect never more than six.
How many spiders are engaged in this work no our behalf? One authority on spiders made a census of the spiders in grass field in the south of England, and he estimated that there were more than 2,250,000 in one acre; that is something like 6,000,000 spiders of different kinds on a football pitch. Spiders are busy for at least half the year in killing insects. It is impossible to make more than the wildest guess at how many they kill, but they are hungry creatures, not content with only three meals a day. It has been estimated that the weight of all the insects destroyed by spiders in Britain in one year would be greater than the total weight of all the human beings in the country.
译文
放过那只蜘蛛
你可能会觉得奇怪， 蜘蛛怎么会是我们的朋友呢？因为它们能消灭那么多的昆虫，其中包括一些人类的大敌，要不是人类受一些食虫动物的保护，昆虫就会使我们无法在地球上生活下去，昆虫会吞食我们的全部庄稼，杀死我们的成群的牛羊。我们要十分感谢那些吃昆虫的鸟和兽，然而把它们所杀死的昆虫全部加在一起也只相当于蜘蛛所消灭的一小部分。此外，蜘蛛不同于其他食虫动物，它们丝毫不危害我们和我们的财物。
许多人认为蜘蛛是昆虫，但它们不是昆虫，甚至与昆虫毫无关系。人们几乎一眼就能看出二者的差异，因为蜘蛛都是8条腿，而昆虫的腿从不超过6条。
有多少蜘蛛在为我们效力呢？一位研究蜘蛛的权威对英国南部一块草坪上的蜘蛛作了一次调查。他估计每英亩草坪里有225万多只蜘蛛。这就是说，在一个足球场上约有600万只不同种类的蜘蛛。蜘蛛至少有半年在忙于吃昆虫。它们一年中消灭了多少昆虫，我们简直无法猜测，它们是吃不饱的动物，不满意一日三餐。据估计，在英国蜘蛛一年里所消灭昆虫的重量超过这个国家人口的总重量。
英文版维基百科中对spider这一词条的解释
Spiders are predatory invertebrate animals that have two body segments, eight legs, no chewing mouth parts and no wings. They are classified in the order Araneae, one of several orders within the larger class of arachnids, a group which also contains scorpions, whip scorpions, mites, ticks, and opiliones (harvestmen). The study of spiders is known as arachnology.
All spiders produce silk, a thin, strong protein strand extruded by the spider from spinnerets most commonly found on the end of the abdomen. Many species use it to trap insects in webs, although there are also many species that hunt freely. Silk can be used to aid in climbing, form smooth walls for burrows, build egg sacs, wrap prey, and temporarily hold sperm, among other applications.
All spiders except those in the families Uloboridae and Holarchaeidae, and in the suborder Mesothelae (together about 350 species) can inject venom to protect themselves or to kill and liquefy prey. Only about 200 species, however, have bites that can pose health problems to humans.[1] Many larger species' bites may be quite painful, but will not produce lasting health concerns.
Spiders are found all over the world, from the tropics to the Arctic, living underwater in silken domes they supply with air, and on the tops of mountains. In 1973 Skylab 3 took two spiders into space to test their web-spinning capability in free-fall.
