Anatomy and Physiology Marine habitats. These primitive multicellular animals lack true tissues or organs. There are no digestive, circulatory or nervous systems. Adults are sessile and use specialised cells called choanocytes to draw water through a system of water canals into the internal cavity called the spongocoel. Nutrients are distributed around the body by mobile cells called amoebocytes.
Anatomy and Physiology Poriferans are Hermaphroditic: no permanent gonads, can become either egg or sperm. Sperm is released from the canals and is drawn into the canals of another sponge. Poriferans have no respiratory or excretory organs; both functions occur by diffusion in individual cells.
Structures Skeletons of sponges can be composed of an organic substance called sponging or they may have calcareous or siliceous skeletons composed of chambers or spicules. Sponges are not like other animals because they do not have a mouth. The tiny holes on their outer layer absorbs water in. The calls in the sponge have a variety of functions and are independent form each other then the cells of other animals. ...Sponges can contain 16,000 other animals inside of them. ...A new type of sponge is found every year. ...One of the largest sponges ever was almost 10 ft wide (around 3 meters long)
Distribution According to the article “Global Diversity of Sponges”, there are around 8,553 accepted species of Porifera, the majority of which (83%) are Demospongiae ; 8% corresponds to Hexactinellida, 8% to Calcarea, and 1% to Homocleromorpha.
Characteristics No definite symmetry. Body Multicellular, few tissues, no organs. Cells and tissues surround a water filled space, but no true body cavity. All are sessile Reproduce sexually or asexually, sexual reproduction either gonochoristic or hermaphroditic. No nervous system Distinct larval stage-planktonic. Lives in aquatic environments, mostly marine All are filter feeders. Often have a skeleton of spicules.
Diversity and classificationPoriferans have an ancienthistory whose first fossilsappeared in Precambriandeposits at the end ofthe Cryogenian "SnowballEarth" period. Scientific Classification: Domain: eukaryota Kingdom: animalia Phylum: porifera Hexactinellida (glass sponges). Sponges are classified as Poriferans. Three different Demospongia (bath sponges). groups of Poriferans are: Calcarea (calcareous sponges).
Pros and ConsPros Cons The constant activity of the The lost of the sponges sponges filtering removes could accelerate the lost of bacteria, small planktonic coral reefs. organisms and organic particles increasing water clarity and quality, linked to live coral reef structure and facilitate its regeneration.