Silicon dioxide is a substance used to manufacture glass. Glass sponges (Class: Hexactinellida) are so named as they possess a skeleton made of silicon dioxide. Some demosponges also have spicules made of silicon dioxide. There are various types of spongin, some of which form fibres to build the skeletal framework. The skeleton of these sponges can include a protein known as spongin. Unlike other sponges, demosponges can also be found in freshwater habitats. Demosponges include the most colourful species and range in size from small encrusting forms to large irregular masses. This group contains 95% of the world's sponges. Demospongesĭemosponges (Class: Demospongiae) are the most commonly seen sponges when snorkelling, diving or walking along the beach. Calcareous sponges are typically found in shallow water and only inhabit marine environments. These sponges are often pale in colour and quite small, generally less than 30 cm. Calcareous sponges also lack spongin, protein fibres. This makes them quite brittle compared to other sponges. Calcareous SpongesĬalcareous Sponges (Class: Calcarea) are distinguished by a skeleton composed entirely of calcium carbonate spicules. There are at least 15 000 species of sponges worldwide and within the Dampier Archipelago 275 species have been recorded. Sponges provide a safe habitat for other animals including small crabs and brittle stars.Īlthough the sponges found washed up on beaches are dull in appearance, live sponges are normally vividly coloured. They are filter feeders and obtain their food as water passes through the network of canals that make up their bodies. This means that they are fixed to the ocean floor and therefore cannot move freely to capture food. In a number of sponge species this protein also contains rod-like structures (spicules) made of calcium carbonate or silica dioxide.Īdult sponges are a sessile group of animals. The skeleton of sponges is usually made up of protein fibres known as spongin. They are multi-cellular animals but do not have any form of tissues or organs. Sponges (Phylum: Porifera) are the simplest animals on the planet and were once considered plants by scientists. Article | Updated 6 years ago Hymeniacidon sp.
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