Impact
Having to do with the effect of ecternal factirx on an
organism, such as the wave impact(physical force) or the
impact of DDT (chemical) on an organism.

Indicator organism
An organism whose life style is so well known that its
presence in a new enviroment helps to
indicate the ecological factors present.

Infauna
Organisms that burrow and live under the surface of the
bottom, as opposed to epifauna.

Isomorphic
Where sporophyte and gametophyte appear alike.