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  • Annelids 密尼利兹

    Underwater scene featuring multiple colorful Christmas tree worms amidst coral and marine life.

    How can this be an animal?
    ::这怎么可能是动物?

    This is a worm. And even though it is blue, this is a Christmas tree worm. These "Christmas tree" structures are actually specialized mouth appendages . Each spiral is composed of feather-like tentacles which are heavily ciliated. These appendages trap prey and transport the food straight towards the worm's mouth. And these worms are annelids.
    ::这是蠕虫。即使它是蓝色的,它也是圣诞树虫。这些“圣诞树”结构实际上是专门的口腔附着物。每个螺旋是由羽毛般的触角组成,这些触角都是大量粘结的。这些附着物捕捉猎物,将食物直接运到虫口。这些蠕虫是鼻孔。

    Annelids
    ::Annelids 密尼利兹

    The phylum Annelida is made up of such as earthworms . Segmented worms are divided into many repeating segments. There are roughly 15,000 of annelids. Most belong to one of three classes. A species in each class is pictured in Figure . 
    ::Annelida 植物由蚯蚓等组成。 分割的蠕虫被分为许多重复部分。 大约有15,000 。 大部分属于三类中的一类。 每个类中的物种在图中显示 。

    Three types of annelids: a marine worm, an earthworm, and a leech.
    Classes of Annelids. The majority of annelids are polychaetes. They live on the ocean floor, so you may not be familiar with them.

    Structure and Function of Annelids
    ::Annelids的结构和功能

    Annelids range in length from less than 1 millimeter to over 3 meters. They never attain the large size of some . Like mollusks, however, they have a coelom . In fact, the annelid coelom is even larger, allowing greater of internal organs . Annelids have other similarities with mollusks, including:
    ::Annelids的长度从不到1毫米到超过3米不等。 它们从来没有达到一些大的大小。 但是,它们像软体动物一样, 也有软体动物。 事实上, annelid coelom甚至更大, 允许更大的内脏器官。 Annelids与软体动物有其他相似之处, 包括:

    • A closed (like cephalopods).
      ::封闭型(类似天花板) 。
    • An consisting of tubular nephridia .
      ::由管状肾脏组成
    • A complete digestive system .
      ::完整的消化系统
    • A brain .
      ::大脑
    • Sensory organs for detecting light and other stimuli .
      ::检测光和其他刺激的感官器官
    • Gills for gas exchange (but many exchange gas through their skin).
      ::煤气交换用Gills(但许多煤气通过皮肤交换)。

    The segmentation of annelids is highly adaptive. For one thing, it allows more efficient movement . Each segment generally has its own nerve and muscle tissues . Thus, localized muscle contractions can move just those segments needed for a particular motion. Segmentation also allows an to have specialized segments to carry out particular functions. This allows the whole animal to be more efficient. Annelids have the amazing capacity to regrow segments that break off. This is called regeneration .
    ::annelid 的分解具有高度的适应性。 首先, 它允许更高效的移动。 每个部分一般都有自己的神经和肌肉组织。 因此, 局部的肌肉收缩可以仅仅移动特定运动所需的部分。 分解还允许有专门的部分来执行特定的功能。 这可以让整个动物更有效率。 Annelid 具有惊人的能力重新生长断裂的部分。 这被称为再生 。

    Annelids have a variety of structures on the surface of their body for movement and other functions. These vary, depending on the species. Several of the structures are described in Figure .
    ::Ananlids在身体表面有各种结构,可以移动和其他功能。这些结构因物种而异。图中描述了其中的一些结构。

    Descriptions of annelid external structures: bristles, paired appendages, feeding tentacles, and suckers.
    Annelid External Structures. Many annelids have bristles and other types of external structures. Each structure is not present in all species.

    Annelid Reproduction
    ::Annelid复制

    Most species of annelids can reproduce both asexually and sexually. However, leeches can reproduce only sexually. may occur by budding or fission. varies by species.
    ::大部分种类的内分泌物既可以生殖性生殖,也可以生殖性生殖,不过,内分泌物只能生殖性生殖,可能发生于萌芽或裂变中,因物种而异。

    • In some species, the same individual produces both and eggs . But worms mate to exchange sperm, rather than self-fertilizing their own eggs. Fertilized eggs are deposited in a mucous cocoon . Offspring emerge from the cocoon looking like small adults. They grow to adult size without going through a larval stage.
      ::在某些物种中,同一个人既产卵,也产卵。但蠕虫是交换精子的配方,而不是自我施肥的蛋。受精的蛋沉积在粘结的椰子中。从鳕子中脱出来,看上去像小成年人。它们长成成人,没有经历幼虫阶段。
    • In polychaete species, there are separate sexes. Adult worms go through a major transformation to develop reproductive organs. This occurs in many adults at once. Then they all swim to the surface and release their gametes in the , where takes place. Offspring go through a larval stage before developing into adults.
      ::在多毛类物种中,有不同的性别。成人蠕虫通过重大转变来发展生殖器官。这种情况同时发生在许多成年人中。然后他们都游到水面,在发生的地方释放他们的调子。在发育成成人之前,幼虫会经历幼虫阶段。

    Ecology of Annelids
    ::Annelids 生态学

    Annelids live in a diversity of freshwater, , and habitats . They vary in what they feed on and how they obtain their food.
    ::安尼利德人生活在淡水、淡水和生境的多样性中,他们的食物和获取食物的方式各不相同。

    • Earthworms are deposit feeders . They burrow through the ground, eating soil and extracting organic matter from it. Earthworm feces , called worm casts, are very rich in plant nutrients . Earthworm burrows help aerate soil, which is also good for plants.
      ::地虫是矿床的饲料,它们钻遍地面,食用土壤并从中提取有机物质。 地虫粪便,叫做蠕虫石,非常丰富的植物养分。 地虫洞有助于土壤通风,对植物也有好处。
    • Polychaetes live on the ocean floor. They may be sedentary filter feeders , active predators , or scavengers . Active species crawl along the ocean floor in search of food.
      ::多毛类动物生活在洋底,可能是定居式过滤器、活性食肉动物或食腐动物。 活性物种在洋底上爬行以寻找食物。
    • Leeches are either predators or parasites . As predators, they capture and eat other invertebrates . As parasites, they feed off the of vertebrate hosts. They have a tubular organ, called a proboscis , for feeding.
      ::龙虾不是掠食者,就是寄生虫。作为掠食者,它们捕食其他无脊椎动物。作为寄生虫,它们从脊椎动物宿主那里食用。它们有一个管状器官,叫做胸骨,用来喂食。

    Comparison of Worms
    ::虫虫比较

    The following table compares the three worm phyla ( Table ).
    ::下表比较了三只蠕虫的phyla(表)。

    Phylum Common Name Body Cavity Segmented Digestive System Example
    Platyhelminthes No No Incomplete Fluke
    Nematoda Roundworm Yes No Complete Heartworm
    Annelida Segmented worm Yes Yes Complete Earthworm

    Summary
    ::摘要

    • Annelids are segmented worms such as earthworms and leeches.
      ::Annelid是分离的蠕虫,如蚯蚓和水蚤。
    • Annelids have a coelom, closed circulatory system, excretory system, and complete digestive system. They also have a brain.
      ::Annelids有一个阴道,封闭的循环系统,排泄系统和完整的消化系统。他们也有大脑。
    • Earthworms are important deposit feeders that help form and enrich soil.
      ::蚯蚓是帮助形成和丰富土壤的重要矿床饲料。
    • Leeches are either predators or parasites. Parasitic leeches feed off the blood of vertebrate hosts.
      ::脊椎动物是掠食者或是寄生虫 寄生虫是脊椎动物宿主的血

    Review
    ::回顾

    1. Discuss the advantages of segmentation.
      ::讨论分割的好处。
    2. Define regeneration.
      ::定义再生。
    3. Polychaete worms have an interesting reproductive strategy. Describe this strategy and infer its adaptive significance.
      ::多毛环节虫具有有趣的生殖策略,描述这一策略并推断其适应意义。
    4. What are deposit feeders?
      ::什么是存款支取者?