Movement of Energy Flashcards
Conservation of energy
Energy is neither created or destroyed.
Gross primary productivity
rate at which energy (E) is captured and converted into chemical bonds by photosynthesis or chemosynthesis.
Most energy enters biosphere via
photosynthesis
Great Oxygenation Event
Photosynthetic bacteria came to be 2.3 billion years ago. This caused the extinction of more than 90% of earths species (anaerobic) at the time.
Photosynthesis is not efficient because
Only 1% of solar energy is captured by the plant and the rest is either reflected or not absorbed by plant
Net Primary Productivity
60% of gross primary productivity is respired. Only 40% of gross primary productivity is used for producer growth and reproduction. This is net primary productivity.
Respiration
Uses oxygen to release chemical energy to drive cellular processes.
Secondary production relies on
primary production
Assimilated energy
energy that a consumer digests and absorbs. NOT EGESTS
Net secondary production (NSP)
Energy converted to first order consumer biomass. (assimilated energy left after respiration by first order consumer)
NSP=GSP - R
Net secondary production = (Food eaten-feces)-respiration
Factors involved in estimating primary production
Change in producer biomass, CO2 exchange, remote-sensing
Change in Producer Biomass
Estimate NPP by harvesting plants to determine mass of growth over a period of time. Underestimation due to herbivory, below ground biomass, and mutualistic exchanges
Co2 uptake
Light/dark bottle experiments measure NPP and GPP. (because plants respire in the dark)
How can remote sensing help us detect biomass?
Measure the absorption of blue and red light and reflection of green light from satellite images. Calculate indices indicating vegetation biomass. Changes in spectral reflectance over time give information on seasonal and annual variation.
NPP is positively correlated with
temperature
NPP is positively correlated with … until …
precipitation, certain point
Energy flows from producers through successive … levels
trophic
Consumption Efficiency
Consumed energy divided by net production energy of the next trophic level.
Assimilation Efficiency
Of the food that is consumed, some is assimilated, the rest is egested (defecated, regurgitated)
Assimilation efficiency= Assimilated energy/Consumed energy
Primary producers have lower … than secondary consumers
Assimilation efficiency
Net production efficiency
Net production energy/assimilated energy
How are net secondary production and assimilated energy different?
Net secondary production includes respiration, while assimilated energy does not.
Ecological Efficiency
Net production energy of a trophic level/ net production energy of the next lower trophic level.
Sees how well the lower level was able to transfer its energy to trophic level.
Generally 5-20% but 10% is a rule of thumb.
Trophic Pyramids
Illustrate distribution of energy or biomass among trophic groups in an ecosystem. Number of trophic levels limited because energy runs out. Aquatic has 5 levels while terrestrial has 3 or 4 levels.
In trophic pyramids, biomass is sometimes inverted in …. because the … eat the … quickly
aquatic systems, consumers, primary producers
In both terrestrial and aquatic systems, energy is … in ….
lower, higher (tertiary) consumer levels
As in other levels energy mostly released as … during respiration in decomposers
heat
