What is a colonial organism, and what does it have in common with a multicellular organism?

Answer 1

A colonial organism lives in colonies: groups of essentially identical organisms. Although they live together, their existence is entirely independent: one or more can be killed without affecting the welfare of the colony as a whole. In a multicellular organism, by contrast, the cells do not have an existence separate from that of the organism as a whole, and if a significant number of cells are killed, the entire organism may die.

Answer 2

A colonial organism is one in which large numbers of individuals live in close proximity, and the entire colony functions much like a single organism. Coral is the commonest example. The Portuguese man-of-war is another. In coral the individuals are all essentially identical. In the man-of-war various individuals in the colony are specialized in structure and function, much like the organs of a single complex organism. It isn't quite accurate to compare "colonial" organisms to "multicellular" organisms, because in many cases the individuals which make up the colony of a colonial species are each multicellular (as in the two examples I mentioned above). But in other cases the individuals in a colony may each be unicellular, as in the photosynthetic, flagellated protist Volvox.

Answer 3

To add to colonial organisms, a lot of them can actually send signals to each other, much like the central nervous system does within muscle tissue. I cant think of the exact names, but different types of bacteria do this. They send out either chemical or mophological signals. Pretty cool stuff. :)