Ecology Ch2 Sec 3 Page 39-42

Ecology links Life Science & Earth Science  Ecology is the study of the complex relationships between living things and their nonliving, or abiotic, environment

Ecosystems  A community of organisms and the environment that the organisms inhabit is an ecosystem  From the Greek oikos—eco –Means house

Distribution of Ecoystems

Ecosystems have ABIOTIC COMPONENTSBIOTIC COMPONENTS SunlightPrimary producers TemperatureHerbivores PrecipitationCarnivores Water or moistureOmnivores Soil or water chemistry (e.g., P, NH 4 +)Detritivores etc.

Elements  Producers—produce their own food –Plants  Consumers—get their energy from eating other organisms  Some consumers get their energy breaking down dead organisms—decomposers  Healthy systems have a balance of producers, consumers, and decomposers

Balancing Forces in Ecosystems  Organisms use matter and energy  Because those amounts are limited so is the number of organisms  The largest population that an environment can support at any given time is called the carrying capacity

Ecological Responses to Change  Events such as forest fires can disrupt ecosystems  Often organisms move elsewhere if other land is available and return when the area has recovered

Succession  Primary—entrance of life to a formerly lifeless area—after a lava flow, after a glacier  Secondary—reentry of life after a disaster  Climax community—when the ecosystem reaches a point of equilibrium

Primary Succession

Secondary Succession

Climax Community  Occurs after many years when the ecosystem reaches maturity and populations remain relatively constant.

Energy transfer  The ultimate source of energy is the sun  Plants capture energy by a chemical process known as photosynthesisphotosynthesis  This energy then flows through the ecosystem through the plants

Energy pyramid Energy is changed in a series of chemical reactions The amount of energy decreases in each transfer as some is lost

Food web  A diagram that shows the feeding relationship among organisms in an environment

Human Stewardship  Changes in ecosystems can affect the ability of an area to sustain a human population  Ecological balances can be affected by human activity

Check out these sites  Food web info htm

Extension  Extensions are information as to where to find extra material about an interesting subject.  If you find a topic you are very interested in, consider doing extra credit research over the topic.