Energy And Ecosystems Flashcards
Biomass
Chemical energy store in an organism which can be passed along the food chain to different tropic levels
Food chains
Show how the energy flows within a biological community. Producers are at the base of all food chains and produce biomass
Consumers rely on producers as their source of energy
Dry mass of tissue per unit area
Dry mass is the mass of an organism after its water had been removed - dried in an oven for several days.
Usually measured in grams or kilograms per meter squared
Calorimeter
Burns biomass and calculates the chemical energy released per gram : made by measuring the change in temperature of a known volume of water
Gross primary production
Chemical energy stored in plant biomass, in a given area or volume
Net primary production
Chemical energy stored in plant biomass after respiratory losses to the environment has been taken into account
NPP = GPP - R
Consumer production
Production of New biomass by consumers
Cannot convert all of the energy available from the previous tropic level into new biomass - energy is lost by respiration and excretion
Net production of consumers
Net production of new biomass by consumers = chemical energy in injested food - ( chemical energy in faeces and urine + chemical energy in respiration
Primary productivity
Refers to the rate of primary production by green plants
Secondary productivity
Rate of secondary production by consumers e.g herbivores and carnivores
Measuring productivity
Measured as biomass in a given area in a given time -
Overcoming limiting factors in farming
- maximising plant exposure to light
- using warmer temperatures in green houses
- irrigation to maximise water supply
Fertilisers
Can be sprayed on fields to maintain nutrient levels in soil which help plants convert energy to biomass
Pesticides
Remove any pests that might spoil the crop which prevents the loss of biomass, herbicides kill weeds and reduce competition for resources
How to reduce energy loss in farming
Limit movement of animals, use heating in barns and antibiotics prevent energy lost to pathogens
