Climate and Vegetation Chapter 1, Lesson 4

Lesson Objectives Identify the factors that affect climate and vegetation. Describe the climate regions of the United States.

Vocabulary Elevation Natural vegetation Arid Tundra

Climate Climate – the weather conditions, including temperature, precipitation, and wind, that occur in an area over a period of time. There are factors that affect the climate of an area: Distance from the equator Distance from oceans and other large bodies of water Elevation (height of the land in relation to the sea level) Areas that are closer to the equator (Southern United States) are warmer than places farther away. Areas that are close to water can be warmed by water in the winter and cooled by the water in the summer. Areas with high elevations are cooler than areas with lower elevations – for every 1,000 feet above sea level, the temperature drops about 3° F.

Earth and the Sun Earth’s orbit around the sun causes changes in seasons – summer, autumn (fall), winter, and spring. Because the earth is tilted on its axis, places get different amounts of sunlight and heat at different times of the year. Some places have four seasons, while other places it is mostly warm all year or mostly cold all year.

Vegetation Weather in the 48 contiguous states generally moves from west to east. Earth is covered with different kinds of natural vegetation, or plant life that grows naturally in a place. The types of vegetation that grows in places depends on several factors including: Soil conditions Temperature Precipitation The amount of precipitation in a place is the single most important factor affecting where different kinds of natural vegetation grow.

Vegetation Regions Most of the United States can be divided into four main vegetation regions. Forest Grassland Desert Tundra Forest regions extend across large areas of both the eastern and western United States. The larger grassland region in the United States stretches across the middle of the country. Only plants that can grown in an arid, or dry, climate can grow in deserts. These plants include short grasses, low bushes, and cactuses. A tundra is a cold, dry region where tress cannot grow. Tundra regions are covered by snow more than half the year.

Vegetation Regions Guess the Region Forest Grassland Desert Tundra