![]() ![]() They are cellular and diploblastic organisms. Sponges are the lower multicellular organisms without having distinct tissue and organ system. Thus, sponges can absorb and withhold fluids. In several freshwater sponges, the contractile vacuole is also present. Also, there are a few wide openings called oscula that spill excess water. The outer surface is punctured by innumerable pores or ostia that provide channels for the entry of water. Their body shape is non-uniform and asymmetrical. Like plants, they cannot move here and there or attach firmly to the sea bed. they are permanently affixed to the solid substratum like clamshells and rocks. The mature sponges are sessile and sedentary, i.e. They can thrive in shallow ocean environments to depths as great as five kilometres. The majority of them exist in marine habitats except for the members belonging to the family Spongillidae, which live in freshwater lakes and streams. The phylum Porifera possesses some unique features than the other multicellular organisms, which we will discuss below: HabitatĪll the poriferans are free-living aquatic animals. It includes members like Sycon, Spongilla, Euspongia, etc. Poriferans have no fixed shape, and all possess an internal skeleton and a large cavity in between called spongocoel. The multiple minute pores in the poriferans are termed ostia, while a common large pore is called the osculum. Poriferans or Sponges possess a spongy appearance. ![]() They are the first multicellular invertebrates that lack a division of labour or the presence of well-developed tissues and organs. Porifera is a phylum of kingdom Animalia that includes pore-bearing species with a spongy texture and no plane of symmetry. This post describes the definition, characteristics, classification and anatomy of the Porifera or Sponge. On further research about their life cycle and feeding system, they were included in the kingdom Animalia. Initially, they were thought to be in the Plantae kingdom because of the green colour and symbiotic relationship with algae. ![]()
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