Term that comes from the Latin molluscus. Mollusks are metazoans with soft teguments, which can appear naked or covered by a shell. These have bilateral symmetry and in their adult phase, a body without segmentation. These beings are invertebrate coelominated protostomes and make up one of the largest phyla within the animal kingdom.
They are the second most numerous invertebrates after arthropods. Among the most popular mollusks we can highlight species such as octopuses, slugs, squid, mussels, clams, among others. According to many experts, it is believed that there are approximately 100,000 living species on the planet.
With respect to its body, it is generally divided into three parts: the head, the feet that are the tool they use to move, and the dorsal visceral mass that is widely developed and that is covered by a mantle.
Mollusks are classified into several classes:
1. Applacophores: they are the most rudimentary, the head and body are not differentiated, they are marine and their mantle is very well developed
2. Monoplacophores: they are characterized by being marine and very old with a single cone- shaped shell and lack of eyes.
3. Polyplatecophores: they have a dorsal face and a flattened body with a well developed foot, their gills are located at the edge of the mantle. They are of marine habitat and are called chitons
4. gastropods: they have a wound to the body well as the shell and one foot to move.
5. Scaphopods: they do not have gills, an elongated body and a tubular mantle on which the cone-shaped shell is located. The sexes are separated and breathe through the mantle. Its head is trunk-shaped and thin tentacles that serve as tactile organs, and also for feeding.
These organisms are included within the kingdom of the metazoans because they are multicellular organisms, that is, their body is made up of a multiplicity of cells; As for its diet, it is heterotrophic, being able to elaborate its own organic substance and it feeds on the organic matter produced by other living beings.
