Définition : Living in the fluid medium (water or air) but unable to maintain their position or distribution independently of the movement of the water/air mass (adapted from Lincoln et al., 1998).
Définition : Colonial organisms are clonal colonies composed of many physically connected, interdependent individuals. The subunits of colonial organisms can be unicellular, as in the alga Volvox (a coenobium), or multicellular, as in the phylum Bryozoa. The former type may have been the first step toward multicellular organisms
