# Chapter 18: Study Guide ## Key Terms and Concepts ### Ecology - Study of the interactions between organisms and their environments. ### Environmental Components - **Biotic factors**: Living components of the environment. - **Abiotic factors**: Nonliving components, including temperature, light, water, and air. ### Habitat - The specific environment where an organism lives. ## Levels of Ecology 1. **Organismal Ecology** 2. **Population Ecology** 3. **Community Ecology** 4. **Ecosystem Ecology** ## Biosphere and Biomes - **Biosphere**: The sum of all the planet's ecosystems. - **Biome**: Major terrestrial or aquatic life zones characterized by vegetation type or physical environment. ### Types of Biomes - **Aquatic Biomes**: Cover 75% of Earth's surface, including: - Marine biomes (oceans). - Freshwater biomes (lakes, rivers). - **Terrestrial Biomes**: Examples include tropical forests, deserts, and tundras. ## Key Environmental Factors - **Greenhouse Gases**: Includes CO2, water vapor, and methane; contributes to global warming. - **Acclimation**: Gradual, reversible physiological adjustment in response to environmental changes.