conversion of light energy from the sun into chemical energy
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trophic level
the position an organism occupies within a feeding sequence (food chain) producers occupy the first level and from then on then primary consumers occupy level 2 as they feed on them, etc.
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higher trophic levels
further down in the chain, the carnivores eating each other less energy and biomass
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lower trophic levels
the producers, the beginning of the food chain more biomass here
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food chain
a model that represents how nutrients and energy are passed from producer to primary consumer and so on in a community
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food web
a diagram that shows how food chains are linked together into more complex feeding systems, representative of the feeding pathways in an ecosystem
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food chain vs food web
chain is a simplified illustration of energy flow, while a food web is a more realistic depiction of an ecosystem. in a web, organisms can have more than one food source/predator, and can occupy more than one trophic level.
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arrows in food chains/webs
the arrows always point in the direction of nutrient and energy flow (not in the direction of who eats who)
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energy stored in organic molecules
sugars and lipids, released by cell respiration to produce ATP
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thermal energy
heat
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the chemical energy produced by an organism can be converted into a number of forms, including:
kinetic, electrical and light energy
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kinetic energy
energy of motion
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electrical energy
energy caused by the movement of electrons.
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light energy
energy produced by the vibrations of electrically charged particles
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exothermic
chemical reaction in which energy is primarily given off in the form of heat
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biomass
the total mass of a group of living organisms biomass diminishes along food chains as less energy is stored expressed as dry weight per unit area
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units of energy per area per time
kJ m^-2 year^-1, the measurement in a pyramid of energy
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ecological productivity
the rate of generation of biomass in an ecosystem, expressed in units of mass per area per time
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primary production
the production of light energy converted to chemical energy in organic compounds by autotrophs.
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gross primary production (GPP)
the amount of chemical energy as biomass that a producer creates in a given length of time
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net primary production (NPP)
the amount of chemical energy that is NOT consumed by respiration (NPP \= GPP-respiration)
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energy source
sunlight is the initial form of energy in almost all communities (in some they use energy derived from chemical processes). light energy is converted into chemical energy via photosynthesis
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energy flow
energy flows through the ecosystem through the different trophic levels in the food chains
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energy loss
not all energy stored in organic molecules is transferred, but instead becomes lost by excretion, being unconsumed, respiration and heat energy (as it cannot be converted)
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energy efficiency
energy transformations are only about 10% efficient as 90% is lost between the trophic levels
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bioaccumulation
the increase of a substance in a particular organism (the zoomed in version of biomagnfication)
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biomagnification
the increase of a concentration of a substance at a particular trophic level (the zoomed out version of bioaccumulation)
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energy pyramid
a model of the amount of energy at each trophic level of a food chain and the flow of energy each level is one tenth of the size of the preceding level
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a numbers pyramid
a model that depicts the number of organisms at each trophic level in an ecosystem, similar to the energy pyramid
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biomass pyramid
a model representing the dried mass of the living organisms at each trophic level of an ecosystem
Studied by 7 people
Note 
Flashcard (32)