Weather is the condition of the air in one place over a short period of time and is always changing. Climate is the kind of weather that an area has over a long period of time. The sun is the source of the earth’s cli- mates. The earth moves around the sun in a yearly orbit, or path, which is called a revolution. Because the earth is tilted on its axis, sunlight hits different regions more directly at certain times of the year. This helps create seasons. Latitude also affects climate. The sun’s rays always fall most directly at or near the Equator. They are least direct near the North and South poles. As a result, most places near the Equator have warm cli- mates while places farthest from the Equator are cold. Prevailing winds, which occur in regular and predictable pat- terns, influence the climate of regions near them. Ocean cur- rents, rivers of warm and cold water moving through the ocean, also affect climate. Precipitation is all forms of water that fall to the earth’s sur- face. The amount of precipita- tion a place receives has a major its climate. Other influences on climate include elevation and nearby bodies of water and landforms. The world can be divided into climate regions. Temperature and precipitation are used to classify climate regions.


1- Name three things that affect climate.
2- Map Skills: In what directions do the prevailing winds move in the low latitudes?


An ecosystem is formed by the interac- tion of plant life, animal life, and the physical environment in which they live. The four ecosystems are forest, grassland, desert, and tundra. Geographers use the term biome to describe major types of ecosystems that can be found in various regions throughout the world. Forest regions include many different types of biomes. A trop- ical rain forest has broadleaf ever- greens, which keep their leaves all year. Rain forests grow where the temperature is warm and great amounts of rain fall. Forests of the middle latitudes consist mostly of broadleaf deciduous trees, which shed their leaves, usually in the fall. Coniferous forests may also grow in the colder parts of the middle latitudes and are named after the cones that protect their seeds. They have long, thin “needles” rather than broad, flat leaves. Most forests are a mixture of biomes. Another distinctive forest biome is chap- arral, which includes small evergreen trees and low bushes, or shrub. The characteristics of grasslands vary depending on their latitudes. Tropical grasslands, or savannas, grow in warm lands near the Equator. Temperate grass- lands are found in cooler climates. Desert ecosystems consist of plant and animal life that can survive with little water. In tundra regions, temperatures are cool or cold. Plant life in this type of region survives in cold temperatures and short growing seasons and without sun- light for most of the winter.


3- What are the four main eco- systems?
4- Chart Skills What kinds of plants are found in chaparral forests?