Hydra
belongs to the phylum Colenterata and the class
hydrozoa. There are over
2,700 species of animals in this class, most of which live in the
ocean. included are certain varieties of jellyfish, such as the
Portuguese Man'O War and the By-The-Wind-Sailor (Velella). The
fresh water Hydra are common and found in ponds, lakes and streams
throughout the world. They are about 5 mm (1/4") long and
consist of about 100,000 cells. The Hydra is unique in many
ways. its body is composed of only two layers and has only seven
different kinds of cells. It
captures food with its stinging tentacles and swallows it whole through a
mouth located at the center of the tentacles. The Hydra feeds on
Daphnia an ostracods and reproduces by budding. The green Hydra
harbors algae within its body as a symbiotic relationship. Hydra
are readily available from science supply companies. |
