2.3 Flows of Energy and Matter Flashcards
Explain the fate of solar radiation as it reaches Earth.
- reflection from Earths surface: 9%
- reflection from cloud surface: 19%
- reflection by scatter from aerosols or atmospheric particles 3%
- abosorption by clouds: 3%
- absorption by dust and molecules in atmosphere: 17%
41% reaches earth surface
pathways of energy through an ecosystem:
- conversion of light energy to chemical energy
- transfer of chemical energy from one trophic level to another with varying efficiencies
- overall conversion of ultraviolet and visible light to heat energy by an ecosystem
- reradiation of heat energy to the atmosphere
how much energy is available to plants on the surface of the earth
1-4%
how much of sunlight is reflected back to space?
Of the energy reaching the Earth’s surface, about 35% is reflected back into space by ice, snow, water and land.
Describe and explain the transfer and transformation of energy as it flows through an ecosystem.
- Matter flows through ecosystems involving transfers and transformations that link them together.
- Not all solar radiation is converted into biomass due to losses from:
Reflection from leaves.
Light not reaching chloroplasts.
Light of unsuitable wavelengths.
Transmission through the leaf.
Inefficiencies in photosynthesis. - The captured energy is converted by green plants into chemical energy (glucose), which is then transferred from one trophic level to the next.
how to calculate ecological efficiency
(energy used for growth (new biomass)/ energy supplied x 100
how are energy storages depicted
boxes in energy-flow diagrams, representing various trophic levels, quantified as the amount of energy or biomass per unit area.
how are energy flows depicted
arrows, often of varying widths, indicating rates of energy transfer or productivity, measured as joules per square meter per day (J m−2 day−1).
productivity definition
the conversion of energy into biomass over a given period of time. It is the rate of growth or biomass increase in plants and animals. It is measured per unit are per unit time, for instance grams per square meter per day (g m−2 d−1).
primary productivity definition
the gain by producers (autotrophs) in energy or biomass per unit per unit time. Either gross or net productivity
gross primary productivity definition
equivalent to the mass of glucose created by photosynthesis per unit area per unit time in primary producers
net primary productivity definition
gain by producers in energy or biomass remaining after allowing for respiratory losses (per unit area or per unit time) - new plant biomass
NPP calculation
NPP = GPP - R
Gross Secondary Productivity definition
total energy or biomass assimilated by consumers
(also known as assimilation)
GPP calculation
food eaten - fecal loss
