topic 10- ecosystems Flashcards
define ‘ecosystem’
a collection of communities and their surroundings (can be living or non-living)
define ‘niche’
the position occupied by an organism in its ecosystem
what is an autotroph?
an organism that makes its own food
what is a decomposer?
breaks down living things (not eating it)
what is a detritivore?
feeds from dead matter
what is meant by a ‘trophic level’?
a trophic level is the position occupied by a group of organisms in a food chain
why are there energy losses in a food chain?
> some parts of organism not eaten
some parts not digested (lost in faeces)
some parts lost via excretion
some lost via heat in respiration
what is ‘biomass’?
what happens to this as you go up the food chain?
total mass or organism in a particular place
as you go up the food chain, the biomass decreases
what is the equation for NPP?
explain all components.
NPP= GPP- respiration
NPP is net primary productivity, the energy left once energy used in respiration is removed
GPP is gross primary productivity, rate energy is going into a plant in an area at a time
how do you calculate energy transfer?
energy available after transfer/energy available before transfer X100
state ways to increase NPP
increase light/water levels
maintain a constant temp
provide nutrients for photosynthesis and growth
how could you manipulate energy from producer to consumer?
harvest animals before adulthood
treat with steroids or antibiotics
selective breeding
maintain constant temp
limit movement
supply food
