1. CHANGE O VER T IME An Introduction

2. F ROGS …

3. P OLAR B EARS …

4. A DAPTATIONS Organisms survive in their environments because they have special adaptations for that particular habitat. Adaptations are characteristics that help organisms survive and reproduce in their environments. Adaptations may include physical structures as well as behaviors for finding food, for protection, and for moving from place to place.

5. H ORSES …

6. C HANGE Earth is approximately 4.6 billion years old and the species that populate our planet have not always been as they are now. Species have become adapted (over time) to the changing environment. If not, they become extinct. This change over time is called evolution. Evolution is a change in a population over time that makes a new species.