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    A cuttlefish moving over coral in an underwater environment.

    Fish or squid?
    ::鱼还是鱿鱼?

    Neither. This is a mollusk, a cuttlefish to be specific. What is a mollusk? Well, to start, mollusks are that are not . There are over 100,000 different mollusks, so there are bound to be some interesting looking organisms , like this one.
    ::这既不是软体动物,也不是一种具体化的切刀鱼。什么是软体动物?首先,软体动物不是。有超过10万种不同的软体动物,所以一定有一些有趣的生物,比如这个生物。

    Mollusks
    ::软体

    Have you ever been to the ocean or eaten seafood? If you have, then you probably have encountered members of the phylum Mollusca . Mollusks include snails, scallops, and squids, as shown in Figure . There are more than 100,000 known species of mollusks. About 80 percent of mollusk species are gastropods . 
    ::你去过海洋或吃过海鲜吗?如果你去过的话,那么你可能已经遇到过海豚莫卢斯卡(phylum Mollusca)的成员。如图所示,软体动物包括蜗牛、扇贝和鱿鱼。已知的软体动物物种超过10万种。大约80%的软体动物是胃动物。

    Common mollusks: a snail, scallop, and squid, showcasing diversity in the phylum.

    This figure shows some of the more common and familiar mollusks.
    ::这个数字显示了一些比较常见和熟悉的软体动物。

    Structure and Function of Mollusks
    ::软体体的结构和功能

    Mollusks are a very diverse phylum. Some mollusks are nearly microscopic. The largest mollusk, a colossal squid, may be as long as a school bus and weigh over half a ton! The basic body plan of a mollusk is shown in Figure . The main distinguishing feature is a hard outer shell. It covers the top of the body and encloses the internal organs . Most mollusks have a distinct head region. The head may have tentacles for sensing the environment and grasping food . There is generally a muscular foot, which may be used for walking. However, the foot has evolved modifications in many species to be used for other purposes.
    ::软体动物是一种非常多样的植物。 有些软体动物几乎是微缩的。 最大的软体动物, 巨大的鱿鱼, 可能只有校车那么长, 体重超过半吨! 软体动物的基本身体图示显示于图中。 主要的区别特征是硬外壳。 它覆盖身体顶部, 并覆盖内部器官。 大多数软体动物有独特的头部区域。 头部可能有触角来感知环境和捕食。 通常有肌肉脚, 可用于走路。 但是, 脚部在很多物种中演进了变化, 用于其他目的 。

    The basic body plan of a mollusk, including structures like shell and mantle.

    Basic Mollusk Body Plan. The basic body plan shown here varies among mollusk classes. For example, several mollusk species no longer have shells. Do you know which ones?
    ::Basic Mollusk body Plan。 这里显示的基本身体计划因软体动物种类不同而不同。 例如, 一些软体动物已经没有贝壳。 您知道是哪一种吗 ?

    Two unique features of mollusks are the mantle and radula (see Figure ). The mantle is a layer of tissue that lies between the shell and the body. It secretes calcium carbonate to form the shell. It forms a cavity, called the mantle cavity , between the mantle and the body. The mantle cavity pumps for filter feeding. The radula is a feeding organ with teeth made of chitin . It is located in front of the mouth in the head region. Herbivorous mollusks use the radula to scrape food such as off rocks. Predatory mollusks use the radula to drill holes in the shells of their prey .
    ::软体动物的两个独特特征是粪便和(见图 )。 粪便是介于贝壳和身体之间的组织层。 它将碳酸钙分解成贝壳。 它形成一个孔洞,称为曼托洞洞,在人与身体之间。 粪便洞泵用于过滤进食。 萝卜是带有基廷制成的牙齿的喂养器官。 它位于头部地区的嘴前方。 Herbivoricmolusks使用萝卜来刮碎诸如岩石以外的食物。 掠夺性软体动物使用萝卜在猎物的外壳中钻洞。

    Mollusks have a coelom and a complete digestive system . Their consists of tube-shaped organs called nephridia (see Figure ). The organs filter waste from body fluids and release the waste into the coelom. mollusks exchange gases with the surrounding air. This occurs across the lining of the mantle cavity. Aquatic mollusks “breathe” under water with gills . Gills are thin filaments that absorb gases and exchange them between the and surrounding water.
    ::Mollusks 拥有一种阴极和完整的消化系统,由管状器官组成,称为肾虫病(见图 )。器官过滤体液中的废物,并将废物排入阴极。软体动物与周围空气交换气体。这发生在腺腔的衬里。水面软体“呼吸”在带刺子的水下。Gills是细细的丝状,吸收气体,并在周围水与周围水之间交换。

    Mollusks have a with one or two hearts that pump blood. The heart is a muscular organ that pumps blood through the circulatory system when its contract. The circulatory system may be open or closed, depending on the species.
    ::Mollusks 有一颗或两颗心脏可以抽血。 心脏是一种肌肉器官, 在其签订合同时通过循环系统抽血。 循环系统可以开放或关闭, 视物种而定 。

    The major classes of mollusks vary in structure and function. You can read about some of their differences in Figure .
    ::软体动物的主要类别在结构和功能上各不相同。您可以从图中读到它们的一些差异。

    Comparison of snail, clam, and octopus characteristics within mollusk classes.

    Use this figure to compare and contrast gastropods, bivalves, and cephalopods
    ::使用此数字比较和对比胃腔、双vals和头状体

    Mollusk Reproduction
    ::Mollusk 复制

    Mollusks reproduce sexually. Most species have separate male and female sexes. Gametes are released into the mantle cavity. may be internal or external, depending on the species. Fertilized eggs develop into larvae . There may be one or more larval stages. Each one is different from the adult stage. Mollusks have a unique larval form called a trochophore . It is a tiny organism with cilia for swimming.
    ::Mollusks 性繁殖。 多数物种的男性和女性是分开的。 网状动物被释放到人文腔中。 视物种而定, 可能是内部的或外部的。 受精卵会发展成幼虫。 可能有一个或多个幼虫阶段。 每个幼虫阶段都与成年阶段不同。 Mollusks 有着一种独特的幼虫形式, 叫做trochophore。 它是一个小生物体, 具有游泳的。

    Ecology of Mollusks
    ::Mollusks 生态学

    Mollusks live in most terrestrial, freshwater, and habitats . However, the majority of species live in the ocean. They can be found in both shallow and deep water and from to polar latitudes. Mollusks are a major food source for other organisms, including humans. You may have eaten mollusks such as clams, oysters, scallops, or mussels.
    ::Mollusks 生活在大多数陆地、淡水和生境中,但大多数物种都生活在海洋中,既可以在浅水和深水中找到,也可以从极地纬度找到。 Mollusks 是其他生物,包括人类的主要食物来源。你可能吃过蛤、牡蛎、扇贝或贝类等软体动物。

    The different classes of mollusks have different ways of obtaining food.
    ::不同种类的软体动物有不同的食物获取方式。

    • Gastropods may be herbivores , predators , or internal parasites . They live in both aquatic and terrestrial habitats. Marine species live mainly in shallow coastal waters. Gastropods use their foot to crawl slowly over rocks, reefs, or soil , looking for food.
      ::气球可能是食草动物、食肉动物或内部寄生虫,它们生活在水生和陆栖生境中;海洋物种主要生活在浅海岸水域中;气球利用脚缓慢地爬过岩石、珊瑚礁或土壤,寻找食物。
    • Bivalves are generally sessile filter feeders . They live in both freshwater and marine habitats. They use their foot to attach themselves to rocks or reefs or to burrow into mud. Bivalves feed on plankton and nonliving organic matter. They filter the food out of the water as it flows through their mantle cavity.
      ::双壳动物一般都是过滤器,它们居住在淡水和海洋生境中,用脚附着在岩石或珊瑚礁上,或钻进泥土中,两头动物食用浮游生物和非生物有机物,在粪便洞洞里流动时从水中过滤食物。
    • Cephalopods are carnivores that live only in marine habitats. They may be found in the open ocean or close to shore. They are either predators or scavengers . They generally eat other invertebrates and fish.
      ::食肉动物是仅生活在海洋生境中的食肉动物,可在公海或近岸发现,或是食肉动物,或是食肉动物,或是食腐动物,一般食用其他无脊椎动物和鱼类。

    KQED: Cool Critters: Dwarf Cuttlefish
    ::KQED: 冷灰熊: 小矮人

    What's the coolest critter in the ocean under 4 inches long? The Dwarf Cuttlefish! Cuttlefish are marine that belong to the class Cephalopoda. Despite their name, cuttlefish are not fish but mollusks. Recent studies indicate that cuttlefish are among the most intelligent invertebrates, with one of the largest brain-to-body size ratios of all invertebrates. Cuttlefish have an internal shell called the cuttlebone and eight arms and two tentacles furnished with suckers, with which they secure their prey. 
    ::长4英寸的海洋中最酷的小生物是什么? 矮人鱼! 鱼是属于Cephralopoda类的海洋生物。 尽管它们的名字是: 鱼不是鱼,而是软体动物。 最近的研究表明, 鱼是最聪明的无脊椎动物,是所有无脊椎动物中最大的脑体型比例之一。 鱼有一个内壳,叫做切托骨,8只手和两只手及两只手手,上面装有吸盘,用来保护猎物的安全。

       

     

     

     

    KQED: The Fierce Humboldt Squid
    ::Fierce Humboldt 鱿鱼(KQED):Fierce Humboldt Squid)

    The Humboldt squid is a large, predatory invertebrate found in the waters of the Pacific Ocean. A mysterious sea creature up to 7 feet long, with 10 arms, a sharp beak and a ravenous appetite, packs of fierce Humboldt Squid attack nearly everything they see, from fish to scuba divers. Traveling in groups of 1,000 or more and swimming at speeds of more than 15 miles an hour, these animals hunt and feed together, and use jet propulsion to shoot out of the water to escape predators. Humboldt squid live at depths of between 600 and about 2,000 feet, coming to the surface at night to feed. They live for approximately two years and spend much of their short life in the ocean's oxygen-minimum zone, where very little other life exists. Because they live at such depths, little is known about these mysterious sea creatures. The Humboldt squid usually lives in the waters of the Humboldt Current, ranging from the southern tip of South America north to California, but in recent years, this squid has been found as far north as Alaska. Marine biologists are working to discover why they have headed north from their traditional homes off South America.
    ::Humboldt鱿鱼是太平洋水域中发现的大型掠食性无脊椎动物。一个神秘的海洋生物,长达7英尺,有10只手臂、尖嘴和狂野食,从鱼到潜水员,几乎无所不能,从鱼到潜水员,一包凶猛的Humboldt Squid攻击。它们以1 000或1 000或1 000多的群落,以时速超过15英里的速度游泳,这些动物一起捕食和喂食,用喷气推进器射出水,以躲避掠食者。Humboldt鱿鱼生活在600至2 000英尺的深水深处,晚上到海面来喂食。它们大约活了两年,在海洋氧最小的海区度过了短命。由于它们生活在这种深处,对这些神秘的海生物知之甚少。Humboldt鱿鱼通常生活在洪堡洋水中,从南美洲的南端到加利福尼亚州,但近年来发现这种鱿鱼离阿拉斯加岛很远。海洋生物学家们正在向北探索为什么它们往南走。

       

     

     

     

    Where's the Octopus?
    ::章鱼呢?

    When marine biologist Roger Hanlon captured the first scene in this video, he started screaming. Hanlon, senior scientist at the Marine Biological in Woods Hole, studies camouflage in cephalopods: squid, cuttlefish and octopuses. They are masters of optical illusion. 
    ::当海洋生物学家Roger Hanlon在录像中捕捉了第一个场景时,他开始尖叫。Hanlon是伍兹洞海洋生物组织的高级科学家,研究甲状腺虫的伪装:鱿鱼、小白鲸和章鱼。他们是光学幻觉的大师。

       

     

     

    Science Friday:  I, Octopus
    ::科学星期五:我,章鱼

    With thousands of chemically-sensitive suckers, color-changing skin, and a brain that literally stretches when they eat, octopuses seem like aliens living in our oceans. In this video by Science Friday, Frank Grasso explains their physical adaptations and how octopuses might process their own sensations.
    ::随着数千个化学敏感的吸尘器,色变皮肤,以及一个在吃东西时真正伸展的大脑,章鱼似乎像生活在我们海洋中的外星人。 在科学周五的这段视频中,弗兰克·格拉索解释了它们的物理适应以及章鱼如何处理自己的感觉。

     

     

    Science Friday: The Unlikely Tale of a Tenacious Snail
    ::科学星期五: 坚固的斯奈尔的奇特故事

    For over 70 years, no one had seen the oblong rocksnail. Declared extinct in 2000, the species was considered to be another native Alabaman mollusk gone and forgotten. But one day in the spring of 2011, biology grad student Nathan Whelan picked up a tiny rock and got a big surprise.
    ::70多年来,没有人见过这颗长长的岩石。 2000年,该物种被宣布灭绝,被认为是另一个亚拉巴马土著软体动物被遗忘的原生。 但2011年春天有一天,生物学研究生内森·惠兰(Nathan Whelan)捡起一块小石头,大吃一惊。

     

     

    Summary
    ::摘要

    • Mollusks are invertebrates such as snails, scallops, and squids.
      ::Mollusks是无脊椎动物,如蜗牛、扇贝和鱿鱼。
    • Mollusks have a hard outer shell. There is a layer of tissue called the mantle between the shell and the body.
      ::Mollusks有一个坚硬的外壳。在外壳和身体之间有一层组织,叫做外壳。
    • Most mollusks have tentacles for feeding and sensing, and many have a muscular foot.
      ::大多数软体动物都有用来喂养和感知的触手,许多动物有肌肉脚。
    • Mollusks also have a coelom, a complete digestive system, and specialized organs for excretion.
      ::Mollusks也有一个螺旋球,一个完整的消化系统,以及用于排泄的专门机构。
    • The majority of mollusks live in the ocean.
      ::大多数软体动物生活在海洋中。
    • Different classes of mollusks have different ways of obtaining food.
      ::不同种类的软体动物有不同的食物获取方式。

    Review
    ::回顾

    1. List the three major classes of mollusks.
      ::列出三大类软体动物。
    2. Describe the basic body plan of a mollusk.
      ::描述软体动物的基本身体计划。
    3. Describe the mantle and radula.
      ::描述护身符和。
    4. What are gills? What is their function?
      ::什么是?它们的作用是什么?
    5. Create a Venn diagram to show important similarities and differences among the three major classes of mollusks.
      ::创建 Venn 图表, 显示三大类软体动物之间重要的相似点和差异 。