Have you ever heard of animals that belong to the phylum porifera? Yes, sponges are often referred to as sponges (sponge) is an animal that mainly lives in shallow water, in the sea, and also in fresh water. This animal is the inspiration for the character of Spongebob Online game SpongeBob SquarePants.
Most sponges live attached to a variety of substrates, such as rocks, shell fragments, corals on the sea. In addition, these sponges are highly dependent on suspended particles in the water as their food.
Porifera are the most primitive multicellular animals because they lack cellular differentiation so their bodies in some ways resemble colonies of protozoa, as cited in Basic Module Classification of Invertebrates by Sundowo Harminto and Vishnu Wardhana.
Unlike most multicellular animals, sponges do not have specialized organs for reproduction, digestion, respiration, sensory or excretion. Porifera are parazoans that have organization at the cellular level only.
Porifera are generally asymmetric, while some other species show radial symmetry. Porifera can reach a size of 0.9 m and bright colors, there are white, green, yellow, purple, and orange. Porifera that are green are usually caused by the presence of symbiotic algae in the body called zoochlorellae.
To recognize sponges, you can understand their morphology or body shape. The following are characteristics of sponges based on their morphology:
- The shape is like a flower vase or bag with a cavity in the body called the spongoselom and the mouth of the bag is called the osculum.
- In simple sponges, the walls of the spongosol cavity have funnels and flagellated cells called choanocytes.
- The body wall of Porifera has small holes like pores called ostium
- There are choanocyte cells that function as triggers for the flow of water from the outside of the body, capture food particles, and capture spermatozoa that come for fertilization.
- There are spicules that vary in shape depending on the species, some are needle-shaped (monoaxons), stars, three-branched (triaxons), four-branched stars (tetraxons) or multi-branched stars (polyaxons).
Classification of Porifera
Quoted from Encyclopaedia BritannicaThere are three classifications of sponges:
1. Calcarea
Class Calcarae is characterized by a skeleton of calcium carbonate spicules, small vase-shaped structures, thin tubes in loose networks or large irregular colonies, mostly small in size, inhabiting shallow waters in all oceans from the tidal zone to a depth from 200 m. up to 800 m. This class has about 300 species.
2. Demospongiae
Demospongiae have a skeleton of silica spicules, spongin fibers, or both. In some primitive genera, this class has no skeleton.
Demospongiae are the most abundant and widespread group of sponges in the sea, from the intertidal zone to a depth of about 5,500 m. There are approximately 4,200 species of the phylum Demospongiae.
Species in this class have very diverse shapes and sizes, some are like thin crusts with a diameter of only a few cm, some are in the form of large cakes with a diameter of 2 m. Carnivore type (cladorhizid sponge) there is no water flow system.
3. Hexactinellida
Finally, there is a classification of hexaactinellida commonly known as glass sponges (glass sponge) because the spicules are made of silica. The spicules are four or six branches and are attached together with cylindrical and conical skeletons.
Hexactinellida has a height of 10-30 cm and lives in the sea, at a depth of 25 m – 8,500 m. These animals cling firmly to hard surfaces, some species rest on soft bottom sediments.
Well, these are the characteristics of sponges and their complete classification. Happy learning, Detikers!
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