Topic 5 - Energy Transfer in Ecosystems Flashcards
What is an ecosystem ?
all the living organisms in an area and all the non living conditions.
What are producers ?
Organisms that make their own food, e.g. plants and algae produce their own food through photosynthesis.
what is the function of photosynthesis in plants?
to release energy for growth and to make useful organic compounds.
what is the biomass of a plant ?
the biological molecules in a plant it can be measures in terms of mass of carbon, or dry mass of tissue per given area.
How is energy transferred through an ecosystem ?
when living organisms eat other organisms.
what is dry mass ?
the mass of the organism with the water removed.
how would you measure dry mass ?
a sample of an organism is dried in an oven set to a low temperature. the same is weighted at regular intervals until the weight is constant so you know that all water is removed. typical unit is km m^-2
how can you estimate the amount of chemical energy in biomass ?
in a calorimeter.
a sample of dry biomass is burnt and the energy released is used to heat a known volume of water.
the chnage in temperature of the water is used to calculate the chemical energy of the dry biomass.
what is the calculation for efficiency of energy transfer ?
(energy out / energy in) x 100
What is the calculation for net primary consumption ?
net primary production = gross primary production - respiratory loss.
NPP = GPP-R
what is net primary production
the energy available to the plant for growth and reproduction
what is the equation for net production of consumers
net production of consumers = chemical energy store - (energy loss by faeces/urine - respiratory loss).
N=I - (F +R )
what is the function of decomposers
they breakdown dead or undigested material, allowing nutrients to be recycled.
how do farmers reduce energy loss in plants
simplifying food webs by eliminating organisms that compete with the organisms being farmed.
weeds- compete with plants for resources (herbicides)
insects - damage leaved, eat crops, cause disease (insecticides)
how can farmers reduce respiratory loss
restricting movement - small pens
heating - indoors and heated