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FOOD CHAINS AND PRODUCTIVITY - Coggle Diagram
FOOD CHAINS AND PRODUCTIVITY
KEY WORDS
PREY
CARNIVORE
PREDATOR
OMNIVORE
CONSUMER (PRIMARY, SECONDARY, TERTIARY)
HERBIVORE
PRODUCER
DECOMPOSERS (SAORIOBIONTS)
what is a food chain?
a visual description of feeding relationships between organisms
each stage in the chain is known as a trophic level
the arrow in the chain represents the direction of energy flow
TROPHIC LEVELS
trophic level 3 = secondary consumer
trophic level 4 = tertiary consumer
trophic level 2 = primary consumer
trophic level 1 = producer
trophic level 5 = quaternary consumer
Food Webs:
organisms do not rely on a single food source
food webs show multiple links between organisms
the start of the food chain:
green plants are the initiators of food chains
they use energy from the sun to make organic compounds
this means that food chains depend on what constraints the plants face
e.g. light intensity/temperature/water/nutrients/space available
Gross Primary Production (GPP);
the total quantity of the chemical energy store in plant biomass in a given area or volume
Net Primary Production (NPP*);
the chemical energy store which is left when losses in respiration have been taken into account
NPP*
is what's available for plant growth, reproduction and is what is passed onto the next trophic level
energy is lost at each trophic level - why?
some of the organism is not consumed
some parts are consumed by cannot be digested so are lost in faeces
some is lost in executory materials such as urine
some is lost as heat energy from respiration
some is lost from movement
what does this energy loss mean?
most food chains only have 4 or 5 trophic levels
total mass of organisms in a particular place - their biomass - is lower at high trophic levels
in general, only about 10% of the energy taken in by an organism is passed on to the next trophic level
Energy Pyramids:
shows the productivity of different trophic levels
the width of each bar shows the total amount of energy in each trophic level
Pyramid of Biomass:
indicate the dry mass of each trophic level
Which is better?
pyramid of energy are the most accurate as they measure energy directly BUT they require the bodies of the organisms to be incinerated
pyramids of biomass require measurement of any dry mass by heating the organism in an oven until they reach constant weight - this obviously kills the organism