Poriferous

Already at the time of Aristotle, around the year 350 (BC), sponges ( poriferous ) were spoken of as marine animals endowed with a great capacity for regeneration . Its consideration in the invertebrate family occurs in the mid-18th century, where they are no longer considered plants and their peculiar water filtration system is detected to feed and reproduce. This magnificent species has around five thousand to ten thousand diverse organisms registered all over the planet. Its great majority is aquatic and almost all of these are found in the oceans.

Poriferous characteristics

Porifers are characterized by being marine organisms with a very simple taxonomic organization, so much so that they do not have a respiratory, circulatory and digestive system . Its body is externally made up of pores that allow it to be absorbed from the flow of water, a process by which it achieves its respiration, feeding, and reproduction. On the other hand, the aquatic world is fundamental for the existence of these species since even to move they depend on the flows of the currents.

Classification of porifers

The classification of porifers is based on the presence or absence of spicules, their composition and their shape .

They are classified into three groups:

• Calcareas: Sponges of this class have their spicules formed of calcium carbonate and do not have sponge fibers. They are usually small and pale in color.
• Hexactinellids: Also known as siliceous sponges, they present silica spicules and their appearance is glassy. They are animals of hot seas and live in considerable depths.
• Demosponges: They behave like sponges without spicules such as the bath or kitchen sponge, which maintain their shape thanks to sponge fibers, a protein close to silk. It is the class in which most sponges are found. They are generally of bright colors such as red, green and blue due to the granules found in the internal part of the sponge cells.

Reproduction in porifers

Poriferous reproduction can be achieved in two ways : asexually , through germination from the fragmentation of its own organism, thus giving birth to a new one; and sexually by expelling eggs into the water.

In the case of fragmentation, part of the sponge is separated from the rest of the body and it manages to regenerate the missing parts, thus giving rise to a new organism. This is achieved from the simplicity of its taxonomy.

Generally, even though hermaphrodite sponges have the ability to reproduce sexually , this process occurs when they are made up of choanocytes and ovules and are fertilized by different organisms.

After the oviparous species expels the sperm into the aquatic environment and these manage to enter another sponge of viviparous origin through the pores, fertilization occurs until giving life to a new organism.

Feeding in the poriferous

This species has a diet based on microscopic particles, bacteria, protozoa and green algae or cyanobacteria . It could also be the case for some carnivorous species that feed on tiny crustaceans .

Due to the particularity of its diet, and by not having mouths, this species feeds through pores on the outside of its body, with which it can capture water from its habitat. This passes through a filter where they absorb the necessary nutrients for their diet. Process that is essential for the cleaning of marine waters, since even the smallest poriferous could filter around 20 liters a day.

The sponge captures microorganisms and particles, absorbs them through the pores, achieving 80% of their nutrition.

Breathing

Sponges or porifers have pores on the outside of their body, which allows them to feed and breathe from the absorption of excessive amounts of water.

During the absorption of water, the porifers obtain the oxygen dissolved in it. The porifer has the ability to purify carbon dioxide and ammonia residues, serving as a natural filter for its habitat. From this process, the oxygen necessary to live is obtained.

This system is not classified within the digestive, respiratory or / and circulatory systems of animals with hearts, since its process through the absorption of water fulfills the operation of these three.

Habitat

Porifers, being aquatic organisms, inhabit mostly in the areas of the seas ; ranging from the coast to seven thousand meters deep. About 150 species of sponges are naturally freshwater .

Due to their motor limitation, since they cannot move on their own, but are dragged by water currents, they live stuck at the bottom, just like a plant. Some of these species, when they manage to fertilize with others, form a colony, but when they fail to fertilize, they remain solitary.

Examples

Among the most well-known poriferous animals, one can highlight from the Spongiidae family the poriferous popularly called horse sponge. Also, another example of the Petrossidae family is the barrel sponge.