Hydra viridissima is commonly called green hydra because of its distinctive colour due to the symbiotic green algae Chlorella that lives within its body. They move in a kind of slow somersaulting motion if they feel the need to. They are reproduced by budding.īudding refers to the forming of a lump by the offspring of the parent and they break off as soon as they become big enough to live by themselves. They belong to mostly unpolluted bodies of water and have a low tolerance for pollution. They consist of stinging cells on their tentacles and are microscopic in size. Hydra is classified under the phylum cnidaria and belongs to the class hydrozoa. They have a central opening through which they take in food and expel waste. Their body is tubular and radially symmetric.

They are found in freshwater and other water bodies including ditches, ponds, slow-flowing rivers, and streams. Hydra is a simple invertebrate animal, having two layers of body cells. Hydra oligarchies are brown, also known as the brown hydra. A small hydra appears to be transparent in its tentacles and yellowish in its tube-like body. The body of the hydra retracts from sensing any danger and appears to be shorter and rounder. They are characterised by the presence of pores all over the body. Sponges are multicellular organisms belonging to the phylum Porifera. Hydras are attached to some underwater objects, waving their tentacles slowly with the current. It is visible to the naked eye when fully extended. Hydra has a cylindrical and radially symmetric body from 2 to 20 mm in length. Every organism is unique in its shape and characteristic in kingdom plantae.

What cells move water through sponges?