Snails are a common name for mollusk gastropods, which are widely distributed among many wetland types and are one of the most typical and common invertebrate groups in wetlands.
Snails are found on land and in the sea, all over the world. There are about 90,000 species recorded worldwide, of which a smaller one is freshwater, about 12,000 species. The snail has a soft body , often with a spiral shell , a well-developed head with a mouth , eyes , and 1 or 2 pairs of antennae ; the feet are also well developed , located on the ventral surface of the body. When active, the head and feet stick out of the shell.
Conch is a "single residential builder", and the conch shell is its elaborate single housing. The shell of snails is generally spiral-shaped, but in appearance, it has various shapes such as pagodas, cones, spindles and gyroscopes, as well as plates or straw hats.
However, the "architectural" shape of the snail shell, although deceptively simple, is very elaborate. The shell is divided into three layers: inner, middle and outer, the middle layer is the thickest, made of calcite; the outer layer is made of thin, relatively rough colored cuticles as the shell surface, and often decorated with patterns; the inner layer is also very thin, made of aragonite, and is "processed" to be particularly smooth, because this shell is next to the soft, tender flesh of the snail.
Snails have the ability to "make the world home" and the ability to adapt to various living environments, which is related to their wonderful snail shells. The thickness and robustness of the shell can be "designed" and "constructed" according to the natural environment in which it is located. In the bottom of the water with many stones, in order to avoid wear, the shell will grow very thick; some snails live a floating life, and the shell of this kind of snail grows very thin and lightweight; at the bottom of the muddy water, the snail is afraid of falling into the mud and cannot climb out, so the shell mouth and shell have many thorns. The shell can withstand cold, heat, and enemies, and can also walk around on its back, which can be described as an "architectural masterpiece".
In addition to the architectural function of snails themselves, snails in natural wetlands also have the function of maintaining biodiversity and purifying water bodies. As an important benthic resource, snails are mostly in the second trophic level in the food chain and occupy an important position in the complex food web of wetland ecosystems.
Snail feeding activities also have a strong impact on the biomass, productivity and species composition of algae communities. Snails that feed on raw algae can effectively suppress the outbreak of algae in eutrophication lakes in the spring.
However, there are some snails, such as Fushou snails, which reproduce at a fast rate, seriously endangering agricultural production and leading to ecological disasters. Effectively controlling the spread of harmful snails and making good use of beneficial snail groups is of great significance to maintaining human health, agricultural safety and ecological harmony.
This article was scientifically checked by Huang Shaohua, a senior teacher of the second middle school in Chaisang District, Jiujiang City, Jiangxi Province.
Xinhua Network Science Popularization Division
Popular Science China - Scientific principles are one-point
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