Communities and Biomes

The Role of Climate Weather- day-to-day condition of Earth’s atmosphere at a particular time and place Climate- The average, year-after-year conditions of temperature and precipitation in a particular region

The Role of Climate Climate is caused by the interplay of: Trapping of heat by atmosphere Latitude (location on Earth’s surface) Transport of heat by winds and ocean currents Amount of precipitation that results Energy of incoming sunlight; solar energy has VERY IMPORTANT effect on the temperature of the atmosphere

The Greenhouse Effect Carbon dioxide, Methane (CH4), water vapor/gas + other atmospheric gases TRAP heat energy and maintain Earth’s temperature range Similar to the role played by glass windows inside a greenhouse! Greenhouse Effect: The natural situation in which heat is retained by this layer of greenhouse gases

The Greenhouse Effect Greenhouse gases allow sunlight (solar energy) to enter Earth’s atmosphere Much of this energy is converted to heat energy (ENERGY PY.) and then radiated back into the atmosphere However, same gases DO NOT allow heat energy to pass out of the atmosphere/trap energy; to modulate/control Earth’s average temperature

The effect of Latitude on Climate Earth is sphere tilted on its axis; solar radiation strikes different parts of Earth’s surface at angle that varies throughout the year At equator- Noon all year, Sun directly overhead At Poles-Sun much lower in sky for months at a time Therefore, more heat delivered to equator vs. poles

The effect of Latitude on Climate As a result of differences in latitude and thus, the angle of heating, Earth has (3) main climate zones: polar, temperate and tropical Polar- cold areas;sunlight strikes at low angle Tropical-hot areas; receive direct sunlight all year Temperate-moderate temperature; between other two zones

Heat Transport in Biosphere Unequal heating of Earth’s surface drives winds and ocean currents Results in the transport of heat throughout biosphere Winds form-warm air rises while cool air sinks Therefore, heated air at equator rises while cooler air at poles sinks Upward movement of warm air/downward movement of cool air = air currents/winds that move heat throughout atmosphere; climates affected! Similar effects occur in oceans; Ocean Currents!

Community Community- Interaction of numerous populations of organisms in one defined area Limiting factors- environmental factors that affect an organism’s ability to survive in its environment (food availability, predators, and temperature) Limiting factors is any abiotic/biotic factor that restricts the existence, numbers, reproduction or distribution of organisms

Succession Succession- the orderly, natural changes and species replacements that take place in a community Succession occurs in stages; different species at different stages create conditions that are suitable for some organisms and unsuitable for others This change can take decades or centuries for one type of community to succeed another

Succession Primary succession- The colonization of new sites by communities of pioneer organisms Pioneer organisms- those organisms able to “create” appropriate living conditions for other species from nonliving materials Ex. LICHEN = THE PIONEER ORGANISM

Primary Succession

Succession After some period of time, primary succession slows down and, after many changes in species composition, the communities become fairly stable Climax Community- A stable, mature community that undergoes little to no change in species Usually, pioneer organisms produce soil for autotrophs/producers to colonize and grow Subsequently, Primary and Secondary consumers colonize the same environment, once conditions are correct for growth

Succession Secondary succession- Sequence of community changes that takes place after a community is disrupted by natural disasters (flood, forest fire or hurricane) or human actions/inactions (farmer leaving field to fallow) Difference between two forms of succession: a. secondary succession occurs in the PRESENCE of SOIL and environment PREVIOUSLY COLONIZED with living organism b. Seconary succession occurs at a much faster rate

Secondary Succession