定義： 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
定義： Gravel is an environmental material which is composed of pieces of rock that are at least two millimeters (2mm) in its largest dimension and no more than 75 millimeters.
定義： Component found in mineralized skeletal tissue, (a specialized form of biogenic tissue in which the extracellular matrix is mineralized, and which functions in mechanical and structural support.)
定義： Capable of the biological process in which new individuals are produced by either a single cell or a group of cells, in the absence of any sexual process.
定義： A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
