Since sponges cannot move, each individual can only fertilize its own egg during sexual reproduction1/1/2024 ![]() However, some sponges may move as amoeboid cells at the base move. Members of Porifera are sessile since they are attached to the substrate. There is no parental investment beyond release of gametes. ( Brusca and Brusca, 2003 Wörheide, 2002) Fertilized eggs will develop into free-swimming larvae. Sperm and eggs are released in the water, and most species cross fertilize. Choanocytes give rise to egg and sperm cells, and archaeocyte cells also give rise to egg cells. Being hermaphroditic, sperm and eggs can be reproduced, sequentially or at the same time. Most all sponges can reproduce asexually, by regenerating tissues. Three sclerocytes will fuse to form spicules in intercellular spaces. Sclerocytes, also in the mesohyl, accumulate calcium to produce spicules. These cells are totipotent, meaning they can develop into any cell type. Acheocytes are large cells with large nuclei. Sponges have different amoeboid cells in the mesohyl. The young break out of the parent's mesohyl, and become free swimming larvae, but not for more than two days. The larval stage has outer flagellated cells, often with spicules. Development of fertilized eggs takes place within the sponge. Reproduction occurs asexually by budding and sexually. Most Calcarea are 10 cm less in height, and are dull in color, although some colorful species are known. Other groups of sponges have microscleres, which are smaller reinforcing spicules. The calcium carbonate spicules are only megascleres, or large structural spicules. ( Wörheide, 2002)Ĭalcarea is the only class with asconoid and syconoid construction. ![]() In tropical regions they are associated with coral reefs. ![]() ( Wörheide, 2002)Įxclusively marine and mainly in temperate regions, Calcarea sponges are usually found in shallower, sheltered waters less than 1000 m. ( Wörheide, 2002) Geographic RangeĬalcarea sponges are found throughout the oceans, but are mainly in temperate areas. ![]() There are about 400 described species of sponges in the Calcarea group. ![]()
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