Chlorophyll
Group of pigments that produce the green hue of plants, essential to photosynthesis.

Decomposer
A plant or organism that feeds on dead material and causes its mechanical or chemical breakdown.

Ecosystem
The interacting system of a biological community and its nonliving environment; also, the place where these interactions occur.

Environment
The sum of all external conditions and influences that affect the development and, ultimately, the survival of an organism or group of organisms.

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.

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

Stomata
Microscopic openings in the surface of a leaf that allow gases to pass in and out.

Species
A population of organisms composed of related individuals that resemble one another and freely breed among themselves.

Snags
Standing dead trees from which most of the branches have fallen. Snags frequently provide homes for wildlife.