Climate and Terrestrial Biodiversity Chapter 7 7 1

Climate and Terrestrial Biodiversity Chapter 7

7 -1 What Factors Influence Climate? § Concept 7 -1 An area's climate is determined mostly by solar radiation, the earth’s rotation, global patterns of air and water movement, gases in the atmosphere, and the earth’s surface features.

7 -1 What Factors Influence Climate? § Weather is a local area’s short-term physical conditions such as temperature and precipitation. § Climate is a region’s average weather conditions over a long period of time. “Climate is what we expect, weather is what we get. ” -- Mark Twain

7 -1 What Factors Influence Climate? § Climate varies from place to place because the air circulation in the lower atmosphere due to: 1. Uneven heating of the earth’s surface by the sun 2. Rotation of the earth on its axis 3. Properties of air, water, and land

7 -1 What Factors Influence Climate? 1. Uneven heating of Earth’s surface by the sun: • • Equator vs. poles – round planet Earth’s tilt – 23. 5º Albedo – how strongly it reflects light Insolation – solar radiation received by a given area in a given time (k. Wh/m 2/day)

7 -1 What Factors Influence Climate?

7 -1 What Factors Influence Climate? 2. Rotation of Earth on its axis • • • Rotation is FASTER at equator than poles…causes the Coriolis Effect – the deflecting of air masses by the rotation of the Earth Also causes complex global air circulation Wind belts produce ocean surface currents

7 -1 What Factors Influence Climate? If the Earth didn’t rotate, we could expect wind to flow in the following manner…

7 -1 What Factors Influence Climate? Instead it looks like this…

7 -1 What Factors Influence Climate? 3. Properties of air, water, and land • Convection cells form due to interaction between air/water/land

7 -1 What Factors Influence Climate?

7 -1 What Factors Influence Climate? § Heat and moisture are distributed over the earth’s surface by vertical air currents, which form six giant convection cells at different latitudes.

7 -1 What Factors Influence Climate? § Ocean Currents are caused by: • Prevailing wind belts • Earth’s rotation § Ocean currents influence climate by distributing heat from place to place. § The temp. of the water affects the temp. of the air

7 -1 What Factors Influence Climate? Generalized Map of the Earth’s Current Climate Zones

7 -1 What Factors Influence Climate? § The Greenhouse effect keeps the entire planet warmer than it would be without it § Greenhouse gases: • • Water vapor – H 2 O Carbon Dioxide – CO 2 Methane – CH 4 Nitrous Oxide – N 2 O

7 -1 What Factors Influence Climate? The Rain Shadow Effect § Interactions between land oceans and disruptions of airflows by mountains and cities affect local climates. § Microclimate – local and regional climates different than the larger regional climate

7 -2 How Does Climate Affect the Nature and Locations of Biomes? § Concept 7 -2 Differences in average annual precipitation and temperature lead to the formation of tropical, temperate, and cold deserts, grasslands, and forests, and largely determine their locations.

7 -2 How Does Climate Affect the Nature and Locations of Biomes? § Climate Affects Where Organisms Can Live § Biomes – large terrestrial regions characterized by similar climate, soil, plants, and animals • Biomes vary by, and are determined by: • Latitude and elevation • Annual precipitation • Temperature