Usually, a characteristic that we associate with animals is their ability to move from one place to another, since, through movement, they manage to perform many of their vital functions, such as feeding, reproducing, escaping from predators and even migrating in some cases.
However, not all animal species have this ability, but there are certain animals that do not move. Although they can make certain movements to achieve, for example, feed themselves, they do not move from one place to another or do so in a very limited way. Read on and discover these animals that do not move in this article.
A classic example of non-moving animals are corals, which belong to the Cnidarians and to the Anthozoa class. Many species of corals form reefs, which are typical colonies consisting of calcareous skeletons produced by the various polyps that, in large numbers, make up the colony. These individual polyps are genetically the same.
Each polyp is a sack-shaped animal with a single opening located in the upper central area, which corresponds to the mouth. In it, there are a series of tentacles that, in some cases, they use to hunt and to feed.
Corals can reproduce sexually and asexually. In sexual reproduction, they have a larval phase in which they are mobile, although they look for a suitable area in the marine substrate to fixate and form the colony, which will be immobile for the rest of their lives.
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Sea sponges are a group of aquatic animals that belong to the edge of the poriferous. The vast majority are marine and very few are found in freshwater. Like all the animals in this article, they are characterized by being sessile. That is, they are immobile animals. In addition, porifers have the peculiarity of not forming tissues. On the contrary, they are made up of cells that are capable of transforming into various cell types according to the needs of the animal.
Unable to go after food, they use their entire body to nourish themselves. This is formed by a series of pores through which the water enters, which circulates to a specialized chamber, made up of particular cells, where the filtration of the liquid takes place and the retention of the nutrients that the animal requires and that will be processed. or digested intracellularly, since sponges lack a digestive system. Finally, the water leaves the body through its only opening, located at the top. Do you know How long do parrots live?
Sea anemones are another example of animals that do not move. They belong to the phylum of the cnidarians and to the anthozoa class. Its sessile life passes on various types of marine substrates, which can be rocks, sand or even the shells of some animals.
The body of the anemones is cylindrical in shape and has a base without a hole that is fixed to the substrate. At the other end is the animal’s mouth, surrounded by various tentacles. The latter structures are equipped with organelles that contain specialized cells that produce a toxic stinging substance, which can be used for defense or to capture prey.
These cnidarians have a wide maritime distribution in the world, being found in different temperature ranges. They can also live at different depths and are even able to resist out of the water thanks to a temporary protection mechanism that allows them to fill with liquid and retain it so as not to dry out.
Barnacles belong to the group of crustaceans. They are marine animals that in their adult life are characterized by being totally sessile, living strongly attached to various substrates, such as rocks, although they even have the ability to adhere to different boats, which is inconvenient when the number of barnacles is numerous. since they interfere with browsing speed. Some of these animals occupy the intertidal zone, which implies that they can be exposed to desiccation by the action of the wind.
One of its main characteristics is to be covered by a calcareous-type shell , from which structures known as cirrus clouds come out, which they use to retain the nutritional particles with which they feed. However, some depend on the movement of the water, more than its cirrus, to be able to feed themselves, since they manage to nourish themselves through the circulation of the liquid.
This group corresponds to the phylum Bryozoa, which is made up of various species of animals that do not move in their adult phase and that form colonies. They are sometimes known as moss animals, given their similar appearance to these plants. They live on various types of substrates, such as rocks, sand, and even some types of algae. Most of the species are marine, although there are a few that inhabit freshwaters.
As for food, they are nourished by filtration and use the presence of a crown of tentacles that produces a stream of water so that the food, mainly made up of phytoplankton, reaches the cilia, responsible for trapping the nutrients that will later be brought to the animal’s mouth.
The blue mussel ( Mytilus edulis ) is a species of bivalve mollusk that, although in its early stages of life it has the ability to move, when it is a well-developed juvenile adult it is permanently attached to a substrate. It is located at depths between 5-10 meters, but also frequently in intertidal zones.
A peculiarity of these animals is their ability to withstand freezing temperatures for a few months. They filter feed on phytoplankton and zooplankton. When they settle permanently, they do so by agglutinating, so it is common to observe the groups of these animals, which is detrimental to older individuals, who end up suffocated by the young that adhere to them.
Despite the name of this group of cnidarians, not all are shaped like a bird’s feather. Specifically, the comparison can be made with those belonging to the suborder Subselliflorae. Marine feathers, although they can change their location, are really sessile, since they anchor in the sandy substrate with the base of the body and remain there, positioning themselves with the currents and forming colonies.
Their bodies are made up of polyps that specialize in various functions, for which they undergo changes. Among these functions we find subjection to the substrate, feeding and reproduction.