T7 trophic levels in an ecosystem Flashcards
what does a food chain show
describes the feeding relationships between organisms and the resultant stages of biomass transfer
what are trophic levels
stages in a food chain
how are trophic levels represented
numbers, starting from 1
after 1, numbered according to how far along the organism is in the food chain
what is trophic level 1
plants and algae which make their own food through photosynthesis - producers
what is trophic level 2
herbivores which eat producers - primary consumers
what is trophic level 3
carnivores that eat herbivores - secondary consumers
what is trophic level 4
carnivores that eat other carnivores - tertiary consumers
what is an apex predator
carnivore with no predators
how do decomposers break down dead matter
release enzymes which catalyse the breakdown of dead material into smaller molecules
soluble small food molecules then diffuse into the microorganisms
what is biomass
dry mass of all the living organisms in an area
why is dry mass used for biomass
because wet mass varies as the volume of water in the organism varies
equation of efficiency of biomass transfer
= (energy transferred/total energy available) x 100
what percentage of the incident energy from for photosynthesis do producers transfer
1%
what percentage of the biomass from one trophic level is transferred to the level above it in feeding
approx 10%
why are biomass transfers not 100% efficient
energy is lost:
egestion (removal of faeces)
excretion (removal of waste products)
respiration (loss of CO2 and water) in which large amounts of glucose are used
production of inedible bones and shells
