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Porifers


Porifers, also known as sponges or simply sponges, probably appeared about 1 billion years ago. They are supposed to originate from unicellular, heterotrophic beings that cluster into colonies.

See the text:

Maybe when you shower, you might like to lather up using a synthetic sponge made of plastic or rubber or a vegetable loofah.


Synthetic Bath Sponges


Vegetable Loofah

But have you ever thought about taking a bath lathering up with some animal skeleton?

Prior to the invention of synthetic sponges, natural sponges were widely used by people for bathing and household cleaning, for scrubbing pots and cups, for example.

The natural sponge is the soft skeleton of certain species of porous group animals; These skeletons are made of a tangle of delicate fibers of a protein called spongin.

These animals have no tissues well defined and have no organs and neither systems. They are exclusively aquaticpredominantly marines, but there are some species that live in freshwater.

The porifers live fixed rocks or submerged structures such as shells where they can form colonies of varying color. They can be found from the shallowest regions of the beaches to depths of approximately 6,000 meters. They feed on organic debris or microorganisms they capture by filtering the water that enters their body, as we will see below. In turn, they serve as food for some species of animals, such as certain mollusks, sea urchins, starfish, fish and turtles.

Organization of the body of porifers

The body of a porous has cells that have a certain division of labor. Some of these cells are arranged in such a way that they form small holes called pores, all over the animal's body. That's why these beings are called porifers (from Latin porus: 'pore'; ferre: 'carrier').

Note in the diagram below that water enters the animal's body through the various pores in its body. It then reaches a central cavity called atrium. Also note that the body wall is lined externally by flattened cells that form the epidermis. Already internally, the body wall is lined with cells called choanocytes.

Each choanocyte It has a long scourge. The beating of the flagella promotes a continuous flow of water from the environment to the animal's atrium. This water is mixed with organic debris and microorganisms, which are captured and digested by the coanocytes. The digested material is then distributed to the other cells of the animal. Because digestion takes place inside cells, porifers are said to have intracellular digestion.

Porifers are animals filters, since they filter the water that enters your body, removing food and gas oxygen from it. Thereafter, waste water from the metabolism of these animals is discharged into the environment through an opening called kiss.

The sponge skeleton is made up of various types of substances. Among them stand out the spicular of limestone or silica, of various shapes, and a protein network called spongin.

In certain sponges, the skeleton has no spicules, but has a well-developed spongin network. Sponges of this type have long been used for bathing and home cleaning as in the text above.


Spicules that support the body of porifers.


Spike in Detail - Electron Microscopy