昆虫 - 高级

What dominates life on Earth?
::是什么主宰了地球上的生命?

Well, by numbers, it's not humans. This may look like a scary creature from your worst nightmare, but it wouldn't hurt a fly. In fact, it is a fly! This picture shows the charming portrait of a horsefly, up close and personal. Those big, striped, colorful orbs are its . Did you ever look through a kaleidoscope? If so, then you have an idea of what the world looks like to a horsefly.
::从数字来看,它不是人类。 它看起来像一个可怕的生物, 它来自你最糟糕的噩梦, 但不会伤害一只苍蝇。 事实上, 它是一个苍蝇! 这幅图片显示了一只马蝇的迷人的肖像, 近距离和私人的。 那些大、 条纹、 色彩多彩的金刚鹦鹉是它的。 你曾经通过千叶眼看过吗? 如果是这样的话, 那么你就会知道 一只马蝇是什么样的世界。

What other organs do insects, like this horsefly, have? Besides sensing their environment, what other functions do their organs serve?
::昆虫还有别的器官吗?

Characteristics and Classification of Insects
::昆虫的特点和分类

It is humbling to realize that it is insects, not humans, that dominate life on this planet. More than half of all known living organisms are insects. There are over one million described , and it is estimated that there may be over ten million species of insects that have yet to be identified or described. There are many thousands of species of the common insects that are most familiar to us. For example, there are roughly 20,000 grasshopper species, 170,000 butterfly and moth species, 120,000 species of flies, 360,000 beetle species, and 110,000 species of bees, wasps, and ants.
::人类认识到是昆虫而不是人类主宰着这个星球上的生命,超过所有已知生物的半数是昆虫。有超过100万的昆虫被描述,估计可能有1 000多万种昆虫尚未查明或描述。我们最熟悉的昆虫有成千上万种。例如,大约有20 000种普通昆虫,170 000种蝴蝶和蛾类,120 000种苍蝇,360 000种贝类,11万种蜜蜂、黄蜂和蚂蚁。

Insects make up a class within the subphylum Hexapoda , and they include most hexapod species. They range in size from less than a millimeter to about 55 centimeters (approximately the length of your arm). An example of a large insect, the walking stick, is shown in  Figure . Although insects can be found in most habitats on Earth, the majority of species are either or aerial. The study of insects is called entomology. Like all , insects have segmented bodies, jointed appendages , and an exoskeleton made mostly of chitin . As members of the subphylum Hexapoda, insects have six legs. They also have additional appendages that are modified for other functions, and we will look at these in more detail in the Insects: Structure and Function (Advanced) concept.
::昆虫在六六甲底亚植物中构成一个类别,它们包括大多数六氯丁二烯物种。它们大小从不到一毫米到大约55厘米不等(大约你的手臂长度)。一个大昆虫的例子,即行棍,见图。虽然在地球上的大多数生境中可以找到昆虫,但大多数物种都是空中的。昆虫的研究称为昆虫学。同所有昆虫一样,昆虫有分解的体、共同的附着物和主要由奇丁制成的外骨骼。作为六氯poda亚生物的成员,昆虫有六条腿。它们还有为其他功能修改的附加物,我们将在昆虫:结构和功能(高级)概念中更详细地研究这些特性。

Body Plan
::机构计划

The body of an insect is divided into three regions: the head, the thorax, and the abdomen. Figure shows the external anatomy of a typical insect. The head houses three sets of appendages modified for feeding (mouthparts), one set of sensory antennae, a pair of compound eyes, and several simple eyes called ocelli . The six legs are attached to the thorax, and the abdomen contains most of the internal organ systems . If there are wings present, they are also attached to the thorax. The abdomen is made up of eleven segments, and these may be reduced or fused in some species.
::昆虫的身体分为三个区域: 头部、 胸部和腹部。 图显示了典型昆虫的外部解剖。 头部包含三组经修改供食用的附肢( 嘴部) 、 一组感官天线、 一对复合眼睛、 以及几个叫做 ocelli 的简单眼睛。 六条腿与口腔相连, 腹部包含大部分内部器官系统。 如果有翅膀, 它们也与胸部相连。 腹部由11个部分组成, 这些部分可以被某些物种缩小或融合。

Classification
::分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类分类

Like the phylum Arthropoda in general, the of insects is in a state of flux. Classification of insects is also particularly complex because of the vast number of species. Figure shows the subdivisions of the class Insecta. You will notice that there are more subdivisions than simply class and order, as is the case with the subphyla in Arthropoda. These extra layers of phylogenetic classification are due to the large diversity of species within this class.
::昆虫的分类也因物种数量众多而特别复杂。图中显示了昆虫类的分类。你会注意到,与阿霍波达的亚植物类和顺序相比,分类比简单的类别和顺序要多。这些多层次的植物遗传分类是由于该类中物种的多样性造成的。

Currently, there are two major subclasses within the insect class: Apterygota and Pterygota. Pterygota includes winged insects and insects that have lost their wings during the course of evolution but arose from a winged ancestor (described as secondarily wingless ). Almost all insect species are found in the subclass Pterygota. Apterygota is a small subclass that includes species, such as bristletails, that undergo very little change during aside from a size increase and sexual maturation.
::目前,昆虫类中有两大小类:Apterygota和Pterygota。Pterygota包括了在进化过程中失去翅膀但来自一个翼状祖先(被描述为无翼)的翅膀昆虫和昆虫。几乎所有昆虫种都出现在小类Pterygota中。Aterygota是一个小小类,包括了除尺寸增加和性成熟外几乎没有变化的树枝等物种。

The subclass Pterygota is further subdivided into two infraclasses: Palaeoptera and Neoptera. This division is based on the complex folding pattern of the wings of insects in the Neoptera infraclass. The wings of insects in the Palaeoptera infraclass do not fold back onto the abdomen. These include mayflies, dragonflies, and damselflies.
::Pterygota 子类进一步细分为两个次等类: Palaeoptera 和 Neptera 。 此区分基于 Neoptera 次等的昆虫翅膀的复杂折叠模式。 Palaeoptera 次等的昆虫翅膀不会折叠到腹部。 其中包括美食虫、 蝗虫 和 水坝本身 。

Insects within the infraclass Neoptera are further subdivided into two superorders: Exopterygota and Endopterygota. The difference between these two groups is related to how they change during development. Species within Exopterygota undergo moderate changes during their development from young, immature organisms to adults, whereas Endopterygota species exhibit rather drastic changes during development. This process of developmental transformation, called metamorphosis , is a prominent feature in the insect class, and you will learn more about the details of insect metamorphosis in a later concept. Exopterygota members include grasshoppers, termites, cockroaches, and lice. Species within the Endopterygota superorder include ants, bees, beetles, fleas, flies, butterflies, and moths.
::亚低级新球菌中的昆虫进一步细分为两个超级序列:异形形形和异形形形形形形形形形形形色色。这两个组的区别在于它们是如何在发育过程中变化的。在发育过程中,异形形形形内物种从年轻、不成熟的有机体到成人都发生了适度变化,而内型形形形形形形色色的物种在发育过程中表现出相当剧烈的变化。这种发展转变过程,称为变形,是昆虫类中的一个突出特征,你会在后来的概念中更多地了解昆虫变形的细节。异形形形形形体成员包括、白蚁、蟑螂和虱子。内形形色色色色色色的物种包括蚂蚁、蜜蜂、贝类、跳蚤、苍蝇、蝴蝶和。

Members of the subphylum Chelicerata, such as spiders and ticks, are often confused with non-flying insects. However, as you learned in the last lesson, chelicerates have four pairs of appendages that are modified to function as legs, while insects have only three pairs. Also, most insects have three distinct body regions, while chelicerates generally have only two. 
::象蜘蛛和虱子等亚植物类切利斯特拉塔的成员往往被与非飞虫混为一谈。 然而,正如你在上一堂课中所学到的, 虱子有四对被修改成腿的附着物,而昆虫只有三对。此外,大多数昆虫有三个不同的身体区域,而虱子一般只有两只。

Summary
::摘要

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• More than half of all known living organisms are insects.
  ::所有已知生物中一半以上是昆虫。
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• As members of the subphylum Hexapoda, insects have six legs.
  ::作为六氯poda子植物的成员,昆虫有六条腿。
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• The body of an insect is divided into three regions: the head, the thorax, and the abdomen.
  ::昆虫的身体分为三个区域:头部、胸部和腹部。
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• Like the phylum Arthropoda in general, the classification of insects is in a state of flux.
  ::昆虫的分类与一般的植物阿托波多植物一样,处于通量状态。
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• Currently, there are two major subclasses within the insect class: Apterygota and Pterygota.
  ::目前,昆虫类中有两大小类:Apterygota和Pterygota。
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• The subclass Pterygota is further subdivided into two infraclasses: Palaeoptera and Neoptera.
  ::Pterygota子类进一步细分为两个次类:Palaeoptera和Neptera。
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• Insects within the infraclass Neoptera are further subdivided into two superorders: Exopterygota and Endopterygota.
  ::Neptera次等内部的昆虫进一步细分为两个超级序列:Exopterygota和Enteryrygota。

Review
::回顾

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1. Where do appendages that function as legs attach to the body of an insect? How many legs do insects have?
   ::昆虫身上有几条腿?
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2. How many sections make up the typical insect body? How does this differ from arachnids?
   ::典型的昆虫体组成了多少个区块?这与虫族有什么不同?
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3. Which group of insects is not included in the large subclass Pterygota?
   ::哪些昆虫不属于大型小类Pterygota?
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4. Which infraclass are dragonflies classified under? How do they differ from the other infraclass?
   ::哪一类次类是划归哪一类的龙虾?它们与其他次类有何不同?
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5. Which superorder contains insects that undergo metamorphosis?
   ::哪个超级序列含有正在变形的昆虫?