Layers of Our Planet • Geosphere: solid part of earth that consists of soil, rock and sediments. • Atmosphere: mixture of gases surrounding earth. • Hydrosphere: All water found on earth. • Biosphere: All areas on the planet that life can exist.
How Does Energy Flow Through an Ecosystem? FOOD CHAIN ENERGY PYRAMID FOOD WEB
Why Does Energy Decrease at Higher Trophic Levels? • Some of the energy is used for organism’s growth. • Lost through heat (entropy) • Fecal Waste
What Are Biomes? • A large region of the planet characterized by a specific climate and certain types of plants and animal communities. • Depends on Temperature & Rainfall (climate)
How do we measure an ecosystem’s productivity? • GPP (Gross Primary Productivity): Rate at which an ecosystem’s producers convert solar energy into chemical energy as biomass (cells, leaves, roots and stems) • NPP (Net Primary Productivity) = GPP – Rate at which producers use chemical energy • Most Productive Ecosystems • Estuaries • Wetlands (swamps and marshes) • Rainforest • Least Productive Ecosystems • Open oceans* • Tundra • Desert • * However the planet has so much open ocean that it produces more of Earth’s NPP than any other ecosystem!
How Do Ecosystems Change? • Ecological Succession: gradual change and replacement of species in a community. • Primary Succession: occurs on a surface where no ecosystem existed before. • Secondary Succession: occurs where an ecosystem already existed (disrupted by humans, animals, storms)