2. * Natural selection- best suited characteristics survive and are passed to offspring * Niche- Role of an organism in its environment

3. * Struggle between organisms to survive as they attempt to use the same resources

4. * Interaction in which one organism kills another for food * Predator-does the killing, snake * Adaptations to help catch/kill prey like poison, speed, echolocation * Prey-is killed, mouse * Adaptations to help escape predators like mimicry, protective covering, false coloring, warning colors, camouflage

5. * Close relationship between 2 species that benefits at least 1 of the species * 3 types of symbiosis

6. * Both species benefit * Lichen-algae and fungi * Clownfish and anemone * Cleaner fish and sharks

7. * One species benefits, the other is neither helped nor hurt * Red-tailed hawks build nests in saguaros

8. * One organism helped, the other is harmed * Parasite hurts its host * Fleas * Ticks * Tapeworms * Mites