46.1 Ecology of Ecosystems
Ecosystems are controlled both by external and internal factors; they can be both resistant or resilient to ecosystem disturbances.
Food Chains and Food Webs
A food web describes the flow of energy and nutrients through an ecosystem, while a food chain is a linear path through a food web.
Research into Ecosystem Dynamics: Ecosystem Experimentation
Many different models are used to study ecosystem dynamics, including holistic, experimental, conceptual, analytical, and simulation models.
Research into Ecosystem Dynamics: Modeling
Conceptual models describe ecosystem structure, while analytical and simulation models use algorithms to predict ecosystem dynamics.
46.2 Energy Flow through Ecosystems
How Organisms Acquire Energy in a Food Web
Autotrophs (producers) synthesize their own energy, creating organic materials that are utilized as fuel by heterotrophs (consumers).
Productivity within Trophic Levels
Productivity, measured by gross and net primary productivity, is defined as the amount of energy that is incorporated into a biomass.
Ecological Efficiency: The Transfer of Energy between Tro...
Energy is lost as it is transferred between trophic levels; the efficiency of this energy transfer is measured by NPE and TLTE.
Modeling Ecosystems Energy Flow: Ecological Pyramids
Ecological pyramids, which can be inverted or upright, depict biomass, energy, and the number of organisms in each trophic level.
Consequences of Food Webs: Biological Magnification
When toxic substances are introduced into the environment, organisms at the highest trophic levels suffer the most damage.
46.3 Biogeochemical Cycles
The elemental components of organic matter are cycled through the biosphere in an interconnected process called the biogeochemical cycle.
The Water (Hydrologic) Cycle
Water has a large effect on climate, ecosystems, and living organisms; it is continuously cycled through the environment .
The Carbon Cycle
Carbon enters the atmosphere in the form of carbon dioxide via the carbon cycle and returns to organic carbon via photosynthesis.
The Nitrogen Cycle
Nitrogen is cycled through the earth via the multi-step process of nitrogen fixation, which is carried out by bacteria.
The Phosphorus Cycle
Phosphorus is an essential element of living things, but, in excess, it can cause damage to ecosystems.
The Sulfur Cycle
Sulfur is deposited on land as precipitation, fallout, and rock weathering, and reintroduced when organisms decompose.