EVERYDAY SCIENCE

Detailed explanation-1: -Definitions of spicule. small pointed structure serving as a skeletal element in various marine and freshwater invertebrates e.g. sponges and corals. synonyms: spiculum. type of: appendage, outgrowth, process. a natural prolongation or projection from a part of an organism either animal or plant.

Detailed explanation-2: -Spicules provide structural support for maintaining the vertical body position, minimize the metabolic cost of water exchange (Riisgard & Larsen, 1995; Uriz et al., 2003), and may even deter predators (Uriz et al., 2003 and the literature cited therein).

Detailed explanation-3: -Each spicule is formed by specialized cells (sclerocytes) that supply mineral ions or particles associated by organic macromolecules to extracellular cavities, where assembly and crystallization in alignment with an initial seed crystal (nucleus) takes place.

Detailed explanation-4: -: a slender pointed usually hard body. especially : one of the minute calcareous or siliceous bodies that support the tissue of various invertebrates (such as sponges) : a spikelike short-lived prominence appearing close to the chromosphere of the solar atmosphere. spicular.

Detailed explanation-5: -Spicules are skeletal structures that occur in most sponges. They provide structural support, as well as deterrence against predators. Large spicules, visible to the naked eye are referred to as megascleres, while smaller, microscopic ones are termed microscleres.