KEY CONCEPT The biosphere is one of Earth’s four interconnected systems.

The biosphere is the portion of Earth that is inhabited by life. The biosphere includes all ecosystems. one of Earth’s systems includes the biota, all the living things in the biosphere

There are three other Earth systems. hydrosphere—water, ice, and water vapor atmosphere—air blanketing Earth’s solid and liquid surface geosphere—geologic features above and below Earth’s surface

Biotic and abiotic factors interact in the biosphere. All four Earth systems are interconnected. The Gaia hypothesis considers Earth as a kind of living organism. Earth systems interact to yield a biosphere capable of supporting life. It was developed by James Lovelock and Lynn Margulis.

KEY CONCEPT Climate is a key abiotic factor that affects the biosphere.

Climate is the prevailing weather of a region. Climate is the long-term pattern of weather conditions. average temperature precipitation relative humidity Key factors shape an area’s climate. temperature sunlight water wind

A microclimate is the climate of a small specific place within a larger area.

Earth has three main climate zones. The three main zones are the polar, tropical, and temperate climates. polar climate: the far northern and southern regions of Earth tropical zone: surrounds the equator temperate zone: the wide area in between the polar and tropical zones

The angle of the Sun’s rays help determine an area’s climate. temperate polar tropical 90 N

Earth’s tilt on its axis plays a role in seasonal change. Solar heating causes movements in both water and air. wind ocean current Warm air and warm water are less dense than cooler air and water, and therefore they rise. Earth’s rotation, water temperature and salinity levels also interact to form currents.

Landmasses also shape climates. Areas closer to water have a different climate than areas further away because land tends to heat and cool more quickly. Inland Areas: larger changes in temperatures less precipitation Coastal Areas: smaller changes in temperatures higher humidity more precipitation

Mountains have an effect on climate. As warm, moist air nears a mountain, it rises and cools. Precipitation occurs on the side of the mountain facing the wind. On the downwind side, drier and cooler air produce a rain shadow. A rain shadow is an area of decreased precipitation. western slope eastern slope

Many organisms survive in a specific climate due to their adaptations. Water holding frog Lives in dry grassland and desserts of Australia, rainy season once a year. Frog survives by burrowing underground where water evaporates more slowly. Moisture loss is further reduced by a cocoonlike structure formed from the frogs shed skin.