定义：Common species and uncommon species are designations used in ecology to describe the population status of a species. Commonness is closely related to abundance. Abundance refers to the frequency with which a species is found in controlled samples; in contrast, species are defined as common or uncommon based on their overall presence in the environment. A species may be locally abundant without being common.
定义：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).
定义：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.
定义：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)
