Food chain
The transfer of food energy from organisms in one nutritional level to those in another.

Food web
The complex and interlocking series of food chains.

Fungi
Small, often microscopic, organisms that lack chlorophyll and cellulose in their cell walls. Fungi are important decomposers of organic wastes.

Growth ring
A layer of wood formed in tree or other woody plant during one growth period.

Growth rings
Layers of wood formed in tree or other woody plant during one growth period.

Adaptation
The process of adjusting to the environment over time. For example a plant with unusually long roots, enabling it to absorb water over a wide area, may be more likely to survive during periods of drought.

Habitat
An area that provides an animal or plant with adequate food, water, shelter, and living space in a suitable arrangement.

Adapted
Suited to certain conditions in the environment.

Herbivores
An organism that feeds on vegetation.

Carbon flux
The process or rate by which carbon moves from one pool to another.