1. ECOLOGY First Edition Chapter 25 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Beaver Dam

3. Florida panther (Puma concolor coryi) resting on the ground, Florida, USA

4. The northern spotted owl inhabits old-growth forests in Oregon, Washington and Northern California. Due to extensive logging in its habitat, the owl's population is declining. It is on the Federal Endangered and Threatened Wildlife and Plants List. Efforts are underway by Federal, State, and private conservation groups to find ways to preserve owl habitat and allow sustainable timber harvest.

5. Polar Bear (Ursus maritimus)

6. Photomicrograph (low power bright field) of Daphnia, also known as a water flea. Daphnia is a member of the crustacea, are found in most fresh water ponds, and will eat algae. Their movement consists of a series of jumps, which are produced by the antennae. The whole body is enclosed within a carapace.