Phylum Poifera

INTRODUCTION: Phylum phylum Porifera is the simplest and is considered the close primitive of the multicellular animals. draw: The word Porifera is derived from Latin.Porus style revolve active and ferra means to bear.So,the Poriferas atomic number 18 pore-bearing animals,commonly called the sponges. HABITAT: all(prenominal) Poriferas ar aquatic.Out of total 5000 species,150 species live in fresh water art object all others be marine. SIZE: The Poriferas contrive in size from fewer millimeter wide to more(prenominal) than one meter tall.They be macroscopic i.e., can be seen with naked eye.Scolymastra joubini-a barrel same glass sponge of Antarctica is more than a metre tall. COMPOSITION: These animals are composed of legion(predicate) cells,however,there is no tissue organization and create no organs.Sponges insufficiency symmetry. In most sponges,the luggage compartment wall is organise of : (1)an outer(a) layer,pinacoderm,made up of cells called pinacocytes a nd, (2)an inner layer,choanoderm,made of whiplike collar cells called choanocytes. Between these pas de deux layers is present gelatinous mesenchyme which may contain amoeboid cells and spicules or sponginfibres. Penetrating the pinacoderm are cylinderical cells called sporocytes. BODY CAVITY: There is a single cavity inside the body,the spongocoel.In most sponges, this spongocoel may be divided into flagellated chambers or canals,lined by flagellated choanocytes. CIRCULATION AND RESPIRATION: Numerous pores are present in the body wall.

The pores through and through which water enters the body are called ostia and pore through which the water leaves the body is known as osculum(main openin g).There are no respiratory or circulatory o! rgans. NUTRITION: Since the sponges are sessile,therefore,these suppose upon the intellectual nourishment coming to them along with water currents brought about by driving force of flagella of choanocytes.The viands includes small animals called zooplankton and plants called phytoplankton which build about 20% of thier nourishment. 80%of thier food consists of detrital organic particles.The food enters the spongocoel cavity through ostia.The food is ingested by the flagellated cells,the choanocytes.The run out products either... If you want to get a sufficient essay, order it on our website: OrderEssay.net

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