Refers to a general condition of process or system, rather than a condition of one of the component pieces. For example, when a plant wilts in response to drought, the entire organism is responding to the effect of loss. Communities of plants and animals and their abiotic environment comprise an ecosystem. Whole ecosystems may respond to an event, such as changes in local climate, by undergoing a systemic change—for example, the composition and abundance of species may be altered, and the functional ecological processes of those organisms would be rearranged.