25 November 2015

Ctenophora

 
Les cténophores sont des organismes marins carnivores, représentés par près de 150 espèces, répandus dans tous les océans du monde. Ils se déplacent grâce à des cils locomoteurs alignés en 8 rangées sur des plaques ciliées et formant des peignes. Ils constituent une bonne part de la biomasse planctonique mondiale. Ils sont aussi connu sous le nom de “comb jelly” ou “groseille de mer” --- Ctenophora is a phylum of animals that live in marine waters worldwide. Their most distinctive feature is the "combs", groups of cilia they use for swimming, and they are the largest animals that swim by means of cilia – adults of various species range from a few millimeters to 1.5 m (4 ft 11 in) in size. Like cnidarians, their bodies consist of a mass of jelly, with one layer of cells on the outside and another lining the internal cavity. Almost all ctenophores are predators, taking prey ranging from microscopic larvae and rotifers to the adults of small crustaceans; the exceptions are juveniles of two species, which live as parasites on the salps on which adults of their species feed. Ctenophores may be abundant during the summer months in some coastal locations, but in other places they are uncommon and difficult to find.