forests. Forest Canopy Research: A Physical and Scientific Frontier Studies of warblers showcase how ecologists approach stud- ies of one or a few species. Other ecologists have been concerned with the ecology of entire forests, lakes, or grass- lands, which they treat as ecosystems. An ecosystem all the organisms that live in an area and the physi- cal environment with which those organisms interact. Many ecosystem studies have focused on nutrients, the raw materials that an organism must acquire from the environ to live