spongin definition biology

Lastly, choanocytes will differentiate into sperm for sexual reproduction, where they will become dislodged from the mesohyl and leave the sponge with expelled water through the osculum. In freshwater sponges, gemmules may survive hostile environmental conditions like changes in temperature and serve to recolonize the habitat once environmental conditions stabilize. Which of the following statements is false? ... What is a spongin? (credit a: modification of work by Parent Géry; credit b: modification of work by Monterey Bay Aquarium Research Institute, NOAA; credit c: modification of work by Sanctuary Integrated Monitoring Network, Monterey Bay National Marine Sanctuary, NOAA). a tough, flexible protein: Term. It must be noted, however, that this pattern of movement has been documented in laboratories, but it remains to be observed in natural sponge habitats. Module 11: Invertebrates. Lastly, choanocytes will differentiate into sperm for sexual reproduction, where they will become dislodged from the mesohyl and leave the sponge with expelled water through the osculum. Use the Interactive Sponge Guide to identify species of sponges based on their external form, mineral skeleton, fiber, and skeletal architecture. Spicules are most conspicuously present in class Hexactinellida, the order consisting of glass sponges. Sponges have multiple cell types that are geared toward executing various metabolic functions. Some of these more-specific cell types include collencytes and lophocytes, which produce the collagen-like protein to maintain the mesohyl, sclerocytes, which produce spicules in some sponges, and spongocytes, which produce the protein spongin in the majority of sponges. In addition, nitrogenous waste produced as a byproduct of protein metabolism is excreted via diffusion by individual cells into the water as it passes through the sponge. In some sponges, ostia are formed by porocytes, single tube-shaped cells that act as valves to regulate the flow of water into the spongocoel. These cells produce collagen to maintain the consistency of the mesohyl. Scottish Anatomist and Zoologist Robert Edmond Grant proposed the name Porifera (L. Porus, pore and ferre, to bear). Pinacocytes, which are epithelial-like cells, form the outermost layer of sponges and enclose a jelly-like substance called mesohyl. Note the similarity in appearance between the sponge choanocyte and choanoflagellates (Protista). In some sponges, porocytes form ostia, single tube-shaped cells that act as valves to regulate the flow of water into the spongocoel. The different cell types in sponges are shown in Figure 1. The sponge’s (a) basic body plan and (b) some of the specialized cell types found in sponges are shown. http://cnx.org/contents/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8. Since gemmules can withstand harsh environments, are resistant to desiccation, and remain dormant for long periods, they are an excellent means of colonization for a sessile organism. Did you have an idea for improving this content? This similarity suggests that sponges and choanoflagellates are closely related and likely share a recent common ancestry. 10/12/2005. In some sponges, production of gametes may occur throughout the year, whereas other sponges may show sexual cycles depending upon water temperature. Spermatozoa carried along by water currents can fertilize the oocytes borne in the mesohyl of other sponges. The difference between this and the mechanisms of other animals is that digestion takes place within cells rather than outside of cells. In addition to the osculum, sponges have multiple pores called ostia on their bodies that allow water to enter the sponge. Choanocytes (“collar cells”) are present at various locations, depending on the type of sponge, but they always line the inner portions of some space through which water flows (the spongocoel in simple sponges, canals within the body wall in more complex sponges, and chambers scattered throughout the body in the most complex sponges). Spicules are most conspicuously present in class Hexactinellida, the order consisting of glass sponges. Choanocytes have flagella that propel water through the body. However, sponge cells are capable of creeping along substrata via organizational plasticity. (a) Clathrina clathrus belongs to class Calcarea, (b) Staurocalyptus spp. Although these animals are very simple, they perform several complex physiological functions. Gemmules are capable of attaching to a substratum and generating a new sponge. In other sponges, ostia are formed by folds in the body wall of the sponge. Porocytes control the flow of water through pores in the sponge body. These cells produce collagen to maintain the consistency of the mesohyl. The structure of a choanocyte is critical to its function, which is to generate a water current through the sponge and to trap and ingest food particles by phagocytosis. The large central opening in the Parazoan body is called the: Describe the different cell types and their functions in sponges. The structure of a choanocyte is critical to its function, which is to generate a water current through the sponge and to trap and ingest food particles by phagocytosis. It is possible for one single sponge cell to survive, reproduce and create a whole new sponge colony. Biology for Majors II. Watch this video to see the movement of water through the sponge body. Some of the spicules may attain giant proportions (in relation to the typical size range of glass sponges of 3 to 10 mm) as seen in Monorhaphis chuni, which grows up to 3 m long. The presence and composition of spicules/spongin are the differentiating characteristics of the three classes of sponges ([Figure 3]): Class Calcarea contains calcium carbonate spicules and no spongin, class Hexactinellida contains six-rayed siliceous spicules and no spongin, and class Demospongia contains spongin and may or may not have spicules; if present, those spicules are siliceous. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional. Sponges are only just classed as animals. Sponge larvae are able to swim; however, adults are non-motile and spend their life attached to a substratum. sponge's "skeleton" Term. Amoebocytes have a variety of functions: delivering nutrients from choanocytes to other cells within the sponge, giving rise to eggs for sexual reproduction (which remain in the mesohyl), delivering phagocytized sperm from choanocytes to eggs, and differentiating into more-specific cell types. Term. Cards Return to Set Details. The food particles are caught by the collar of the choanocyte and are brought into the cell by phagocytosis. Figure 3: (a) Clathrina clathrus belongs to class Calcarea, (b) Staurocalyptus spp. Water entering the spongocoel is extruded via a large common opening called the osculum. Whereas pinacocytes line the outside of the sponge, choanocytes tend to line certain inner portions of the sponge body that surround the mesohyl. This phylum contains about 10000 species; among them, most of the species are Marine and some are freshwater (about 100 species). They do not show movement over large distances like other free-swimming marine invertebrates. Choanocytes have flagella that propel water through the body. amoebocytes: Definition. (common name: yellow Picasso sponge) belongs to class Hexactinellida, and (c) Acarnus erithacus belongs to class Demospongia. Describe the feeding mechanism of sponges and identify how it is different from other animals. Their food is trapped when water passes through the ostia and out through the osculum. sponge cells that carry food particles to epidermal cells: Term. Level. Note the similarity in appearance between the sponge choanocyte and choanoflagellates (Protista). a collagen-like gel and suspended cells for various functions, spicules composed of silica or calcium carbonate. (I)) Spongin fibers: The spongin fibers are made up of . Watch this video to see the movement of water through the sponge body. The morphology of the simplest sponges takes the shape of a cylinder with a large central cavity, the spongocoel, occupying the inside of the cylinder. The presence and composition of spicules/spongin are the differentiating characteristics of the three classes of sponges (): Class Calcarea contains calcium carbonate spicules and no spongin, class Hexactinellida contains six-rayed siliceous spicules and no spongin, and class Demospongia contains spongin and may or may not have spicules; if present, those spicules are siliceous. However, sponges exhibit a range of diversity in body forms, including variations in the size of the spongocoel, the number of osculi, and where the cells that filter food from the water are located.

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