Unit 1, Concept 3 --> Energy Flow
What is a food web?
A food web is a model of an interlocking pattern of food chains that depicts the flow of energy and nutrients in two or more food chains.
What factor do ecosystems depend on?
All ecosystems depend on a continuous inflow of high-quality energy in order to maintain their structure and function of transferring matter between the environment and organisms via biogeochemical cycles.
What cycles are essential for life on earth?
Biogeochemical cycles are essential for life and each cycle demonstrates the conservation of matter
What is GPP?
Gross primary productivity is the total rate of photosynthesis in a given area.
Describe how energy flows in terrestrial and aquatic ecosystems
In terrestrial and near-surface marine communities, energy flows from the sun to producers in the lowest trophic levels and then upward to higher trophic levels.
Describe how light is absorbed in aquatic ecosystems
Most red light is absorbed in the upper 1m of water, and blue light only penetrates deeper than 100m in the clearest water. This affects photosynthesis in aquatic ecosystems, whose photosynthesizers have adapted mechanisms to address the lack of visible light.
What is NPP?
Net primary productivity is the rate of energy storage by photosynthesizers in a given area, after subtracting the energy lost to respiration.
Describe positive and negative feedback loops
Positive and negative feedback loops can each play a role in food webs. ● When one species is removed from or added to a specific food web, the rest of the food web can be affected.
What is primary productivity?
Primary productivity is the rate at which solar energy (sunlight) is converted into organic compounds via photosynthesis over a unit of time.
What is productivity measured in?
Productivity is measured in units of energy per unit area per unit time (e.g., kcal/m2/yr).
Describe the 10% rule
The 10% rule approximates that in the transfer of energy from one trophic level to the next, only about 10% of the energy is passed on.
How can the loss of energy be explained in an ecosystem?
The loss of energy that occurs when energy moves from lower to higher trophic levels can be explained through the laws of thermodynamics.
Describe trophic cascades
Trophic cascades are an ecological phenomenon triggered by the addition or removal of top predators, and involving reciprocal changes in the relative populations of predator and prey through a food chain, which often results in dramatic changes in ecosystem structure and nutrient cycling.
