Jellyfish reproduction

How do jellyfish reproduce? Jellyfish are marvellous creatures with a gelatinous body. It is easy to recognise jellyfish! They have a convex portion called umbrella with numerous tentacles hanging from its margin. The manubrium is a tubular structure hanging from the centre of the umbrella ending with an opening which acts as both mouth and anus. The jellyfish of this video belong to the Phylum Cnidaria and the class Scyphozoa. The word "cnidarians" originates from greek and means "nettle". This name is referred to their ability to inflict painful stings by means of stinging organelles called cnidocysts, contained in the epiderm. This picture shows numerous cnidocysts on the surface of a jellyfish tentacle. These organelles contain a coiled thread often bearing spines. Here discharged cnidocysts and everted threads are showed. The cnidocyst discharge is triggered for example when the human skin or a prey are in contact with a tentacle, the thread is ejected and penetrates in the victim and a toxin is injected in its tissues. How do jellyfish reproduce? Let's see the moonjelly's (Aurelia sp.) life cycle. The life cycle of Cnidarians shows two main stages, the polyp and the medusa (or jellyfish). The polyp lives attached to the bottom while the jellyfish is free-swimming. The polyp presents mouth and tentacles direct upward while in jellyfish they are direct downward. This video shows a polyp few millimetres high. The polyp waits for an imprudent prey, for example a small ...



http://www.youtube.com/watch?v=ct9KyLmnu0I&hl=en

Friends Link : Best Deal Light Price Foreman StreamingPlayer1080pHD