海绵，多孔的一类动物 Sponge, the porous animal

海绵动物是一类多孔滤食性生物体，属于多孔（海绵）动物门。它们有大约5000个物种，分布在各种水域中。它们的形态各异，有块状、管状、分叉状等等。

Sponges (Poriferans) are a group of porous filter-feeding organisms, belonging to the phylum Porifera. They have about 5,000 species, distributed in various aquatic habitats. They have diverse shapes, such as block-like, tube-like, branched, etc. 

海绵是一种栖息在水中的无脊椎动物，意味着它们附着在水下表面并且成年后不会四处移动。然而，在它们的幼体阶段，它们是可以主动或者被动运动的。

Sponges are sessile aquatic animals, meaning that they attach themselves to underwater surfaces and do not move around in their adult stage. However, during their larval stage, they are motile in a certain way. 

虽然有一些淡水海绵的物种，但大多数海绵还是主要生活在海洋环境中，从潮间带到超过8800米的深度都可以找到它们的踪迹。

While there are some freshwater species of sponges, the majority of them are found in marine environments, ranging from tidal zones to depths exceeding 8,800 meters.

海绵是多细胞生物，它们的体内充满了孔和通道，使水能够流过它们。它们由夹在两层薄细胞之间的一片叫做中胶层的凝胶状物质组成。它们的细胞是未分化的，这意味着它们有能力转化为其他类型的细胞并在不同的海绵层之间移动。

Sponges are multicellular organisms with bodies that are full of pores and channels that allow water to flow through them. They consist of a jelly-like substance called mesohyl that is sandwiched between two thin layers of cells. Their cells are unspecialized, which means they have the ability to transform into other types of cells and migrate between the different layers of the sponge.

与其他动物不同，海绵没有特化的系统，如神经、消化或循环系统。相反，它们依靠维持通过体内的水流来获得食物和氧气并排除废物。这种独特的摄食方式是由它们体内的孔和通道所实现的。

Unlike other animals, sponges do not have specialized systems such as nervous, digestive, or circulatory systems. Instead, they rely on maintaining a constant flow of water through their bodies to obtain food and oxygen and remove waste. This unique mode of feeding is made possible by the pores and channels in their bodies.

有些海绵展现出辐射对称性，但很多海绵是不对称的。它们的体型被塑造成最大化水流通过中央腔道的效率。水通过孔进入海绵，沉积营养物质，然后通过称为出水孔的孔洞流出。

While some sponges exhibit radial symmetry, many of them are asymmetrical. Their bodies are shaped in a way that maximizes the efficiency of water flow through their central cavity. Water enters the sponge through pores, deposits nutrients, and then exits through a hole called the osculum.

许多海绵具有由碳酸钙或二氧化硅的骨针（注意西文的专用名词）和海绵丝（或译海绵质，一种特化的胶原蛋白）组成的内部骨架。

Many sponges have internal skeletons made of spicules, which are skeletal-like fragments of calcium carbonate or silicon dioxide, and/or spongin, which is a modified type of collagen protein.

海绵有各种各样的形状和大小，也有不同类型的骨架。一些海绵甚至使用果冻状的中胶层物质作为它们的骨架。但在大多数情况下，中胶会被硅质、碳酸钙或海绵素等矿物质的针状物或纤维加强。

Sponges come in a variety of shapes and sizes, and they also have different types of skeletons. In some sponges, a jelly-like substance called mesohyl serves as their internal skeleton. However, in most cases, the mesohyl is strengthened by spicules or fibers made of minerals like silica, calcium carbonate, or spongin.

寻常海绵（真海绵，此译少见）是最常见的海绵类型，约占所有海绵物种的90%。它们生活在各种栖息地中，甚至可以在淡水中生存。而钙质海绵则仅限于浅海水域，因为在那里，它们更容易生产出它们的碳酸钙骨架。玻璃海绵是所有海绵中最精致的，它们的硅质针状物使它们非常适合于极地冷水区域。

Demosponges are the most common type of sponge, accounting for about 90% of all sponge species. They are found in a variety of habitats and can even survive in freshwater. Calcareous sponges, on the other hand, are restricted to shallow marine waters where it's easier for them to produce their calcium carbonate skeleton. Glass sponges are the most delicate of all sponges, and their silica spicules make them well-suited to the cold and deep waters of the polar regions.

我们看到了海绵动物，并学习到了它们是如何利用自己简单的身体结构，来适应各种环境和挑战的。这告诉我们，即使是简单的生命形式，也有着无限的可能性和创造力。

Here, we saw how sponges use their simple and flexible body structure to adapt to various environments and challenges. They tell us that even the simplest form of life has infinite possibilities and creativity.