Chapter 3Ecosystem Ecology

By 2006, more than 9 million people lived in this small nation, and less than 2 percent of its land remained forested.

Ecosystem Ecology examines interactions between the Living and

Non-Living world• Ecosystem - A particular location on Earth

distinguished by its particular mix of interacting biotic and abiotic components.

Ecosystem Boundariesdon’t need in notes

• Some ecosystems, such as a caves and lakes have very distinctive boundaries. However, in most ecosystems it is difficult to determine where one ecosystems stops and the next begins.

Producers (autotrophs) are able to use the sun’s energy to produce usable energy

through the process called photosynthesis.

Section 2: Energy Flows through Ecosystems

• Cellular respiration is the process by which other organisms gain energy from eating the tissues of producers.

Section 2: Energy Flows through Ecosystems

“Trophic” Energy PyramidThe representation of the distribution of biomass among trophic levels.

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Ecological efficiency- The proportion of consumed energy that can be passed from one trophic level to another.

Caloriesdon’t need in notes

The energy needed to raise the temperature of 1 gram of water through 1 °C

Trophic pyramid

(don’t need in notes)

This trophic pyramid represents the amount of energy that is present at each trophic level, measured in joules (J).

While this pyramid assumes 10 percent ecological efficiency, actual ecological efficiencies range from 5 to 20 percent across different ecosystems. For most ecosystems, graphing the numbers of individuals or biomass within each trophic level would produce a similar pyramid.

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One joule is equal to the energy used to accelerate a body with a mass of one kilogram using one newton of force over a distance of one meter.

•Food Chain: The sequence of consumption from producers through tertiary consumers.

• Food Web: A more realistic type of food chain that takes into account the complexity of nature.

vs.

Ecosystem Productivity

• Gross primary Gross primary productivity (GPP) productivity (GPP)

• The total amount of solar energy that the producers in an ecosystem capture via photosynthesis over a given amount of time.

• Net primary Net primary productivity (NPP) productivity (NPP)

• The energy captured (GPP) minus the energy respired (lost) by producers.