Identify the major biome types of North America, and recognize other major types. Describe the state variables that create these biomes. Largely determined by two factors 1. solar energy and 2. movement of the earth. Light absorbed by earth and water causes heating. Solar energy is most intense when the sun is directly overhead.
Sunlight varies from north to south and south to north in intensity.
Day length and temperature variation are not so great as in temperate regions. Seasonality increases toward the poles. At the poles, there are long cold winters with long periods of darkness and short summers with continual light. As the air rises, it cools and rain falls. As the air moves away from the equator, it becomes drier.