Mollusca
Also known as molluscs, mollusc, mollusks, mollusk
thumb|Cornu aspersum (formerly Helix aspersa)—a common [[land snail]] thumb|Shell of Marisa cornuarietis, a [[freshwater snail]] Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). 86,600 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The number of additional fossil species is estimated between 60,000 and 100,000, and the proportion of undescribed extant species is very high. Many taxa remain poorly studied.
AI overview
Mollusca is a major group of invertebrate animals that includes snails, clams, and related creatures, with around 86,600 known living species making it the second-largest animal phylum. Molluscs matter because they are incredibly diverse and abundant in ecosystems worldwide, though many species remain unstudied and poorly understood by scientists.
AI-generated from the Wikipedia summary — may contain errors.
Species
molluscs
Mollusca
PHYLUM
- KingdomAnimalia
- PhylumMollusca
Habitatmarine, brackish, freshwater
Observations300
本条目需要精通或熟悉相关主题的编者参与及协助编辑。（2014年3月2日） 請邀請適合的人士改善本条目。更多的細節與詳情請參见討論頁。 Cornu aspersum 腹足纲的阿拉伯长鼻螺 软体动物门（学名：Mollusca[註 1]）屬於無脊椎動物，就其物種多樣性而言，是动物界的第二大門，僅次於節肢動物門[2]，其已確認的物種數量估算從8.5萬種到十萬多種[3]不等。软体动物能適應許多不同環境，分布广泛，从寒带、温带到热带，从海洋到河川、湖泊，从平原到高山，陆地、淡水和咸水多種棲息地中都有大量成员，例如蜗牛、河蚌、海螺、乌贼等物種。而在海洋生物當中，比重佔23%的軟體動物更在所有動物排第一位。 軟體動物型態、習性差異甚大，最大的软体动物大王乌贼的腕展开可达12公尺[4] ，最小的螺类卻僅有1厘米長[5]。但是牠們有共同的基本特征，身体無內骨骼且軟，大多数不分节，身體結構可分為头、足、内脏团和外套膜4个部分。部分軟體動物的外套膜會分泌出钙质的硬壳保护身体。外套模的形狀因種類而不同。除了成年期的腹足动物之外，軟體動物的的壳体都是左右对称的[2]。 软体动物大多有壳，如田螺、文蛤等貝類；少數在陸地上的則有蜗牛、蛞蝓；章鱼、烏賊、海蛞蝓的外殼已消失；软体动物多数靠一条肉脚向前滑动，以此移动自己的身体，很多都有一个盘绕的外壳来保护蜗在里面的柔软的身体。 目录 1 特徵 2 主要結構 2.1 頭 2.2 肉足 2.3 内脏团 2.4 外套膜與外套腔 2.5 殼 3 主要系統 3.1 神经系统 3.2 消化系统 3.3 呼吸系统 3.4 循环系统 3.5 泌尿系统 3.6 生殖系统 4 分類 4.1 单板纲 4.2 无板纲 4.3 多板纲 4.4 腹足綱 4.5 掘足綱 4.6 斧足綱 4.7 喙壳纲 4.8 頭足綱 4.9 太陽女神螺綱 4.10 竹节石纲 4.11 软舌螺纲 4.12 其他分類系統 5 习性 6 参见 7 注释 8 參考文献 9 延伸閱讀 10 外部連結 特徵 軟體動物最主要的特徵就是身體柔軟，並無内骨骼，大部分呈左右对称、不分節，牠們外层皮肤會自背部折皱形成外套膜包圍全身，並能夠分泌保护用的石灰质介壳，然而部分軟體動物的外殼已退化(如蛞蝓、章魚[6])或是藏至体內（如烏賊）。斧足類、腹足類的殼表還有生長線，可以看出年齡大小[7]。軟體動物的腹部有肌肉足或腕，但也有的肉足已經退化，是運動器官。 大多数软体动物的头上长有和眼睛一样的触角，用来感知周围的情况，它们有几千颗微小的牙齿，稱為齒舌，是他們多數特有的器官，由多列角质齿板组成，形狀類似锉刀，主要用於攝食。有栉鳃，表面具纤毛，可以激动水流，双壳类可用此過濾水中的食物颗粒。 水生的軟體動物排泄器官为肾，會排出氨或尿素，牠們呼吸器官為鰓，由外套膜形成位於外套与身体之间，可以從流入外套腔的水中吸取氧氣。而像蝸
via GBIF
Research
72,879 papersArticle
29 sectionsContents
- Etymology
- Definition
- Diversity
- Anatomy
- Mantle and mantle cavity
- Shell{{anchor|Shell}}
- Foot
- Circulatory system
- Respiration
- Eating, digestion, and excretion
- Nervous system
- Reproduction
- Ecology
- Feeding
- Classification
- Phylogeny
- Evolutionary history
- Human interaction
- Uses by humans
- Bioindicators
- Harm to humans
- Stings and bites
- Disease vectors
- Pests
- See also
- Explanatory notes
- References
- Further reading
- External links
thumb|Cornu aspersum (formerly Helix aspersa)—a common [[land snail]] thumb|Shell of Marisa cornuarietis, a [[freshwater snail]] Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). 86,600 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The number of additional fossil species is estimated between 60,000 and 100,000, and the proportion of undescribed extant species is very high. Many taxa remain poorly studied.
Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. They are highly diverse, not just in size and anatomical structure, but also in behavior and habitat, as numerous groups are freshwater and even terrestrial species. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known extant invertebrate species. The gastropods (snails, slugs and abalone) are by far the most diverse class and account for 80% of the total classified molluscan species.