CHAPTER 5

The layer of Earth that contains all living organisms.

A natural association that consists of all the populations of different species that live and interact together within an area at the same time.

The interaction among organisms that vie for the same resources in an ecosystem (such as food or living space).

The totality of an organism’s adaptations, its use of resources, and the lifestyle to which it is fitted.

The study of the interactions among organisms and between organisms and their abiotic environment.

A community and its physical environment.

The passage of energy in a one-way direction through an ecosystem.

A physical law which states that energy cannot be created or destroyed, although it can change from one form to another.

A region that includes several interacting ecosystems.

The biological process that captures light energy and transforms it into the chemical energy of organic molecules, which are manufactured from carbon dioxide and water.

A group of organisms of the same species that live together in the same area at the same time.

The consumption of one species (the prey) by another (the predator).

A physical law which states that when energy is converted from one form to another, some of it is degraded into heat, a less usable form that disperses into the environment.

An intimate relationship or association between members of two or more species; includes mutualism, commensalism, and parasitism.