Topic 5 B Flashcards
(23 cards)
What is biomass?
The mass of living material
What is the order of organisms in an ecosystem?
Producers, primary consumers, secondary consumers, tertiary consumers
How do you measure the biomass?
Mass of carbon or dry mass of tissue per unit area
How to measure dry mass?
Dry the organism in an oven at a low temperature, weigh sample at regular intervals until the mass is constant
What is gross primary production?
total amount of chemical energy converted from light energy by plants
What is respiratory loss?
Loss of gross primary production to the environment as heat when plants respire
What is net primary production?
The remaining chemical energy
What is the relationship between gross primary production, respiratory loss and net primary production?
NPP=GPP-R
How is net production is calculated?
Chemical energy ingested-(CE lost in urine and faeces+energy lost through respiration)
How do you calculate efficiency of energy transfer
(Net production of trophic level/net production of previous trophic level) x 100
What do saprobionts do?
feed/breakdown remains and secrete enzymes and digest food externally (extracellular digestion)
What is mycorrhizae?
When fungi form symbiotic relationships with roots and plants
How do the fungi help plants?
made of long thin strands called hyphae that connect to roots, increase surface area helping to absorb ions from soil and increase uptake of water
What are the four main processes in the nitrogen cycle?
Nitrogen fixation, denitrification, ammonification, nitrification
What happens during nitrogen fixation?
Nitrogen gas from atmosphere is turned into nitrogen containing compounds. Bacteria turn nitrogen into ammonia to form ammonium ions that can be used by plants. Bacteria is found in soil or root nodules
What happens during ammonification?
Nitrogen compounds in dead organisms are turned into ammonia by saprobiotes, forming ammonium ions
What happens during nitrification?
Ammonium ions are turned into nitrogen compounds (nitrates), Ammonium ions, nitrites, nitrates
What happens during denitrification?
Nitrates are converted into nitrogen gas by denitrifying bacteria (aerobic respiration such as waterlogged soil)
What happens during the phosphorus cycle in soil?
Phosphate ions are released into the soil by weathering which are taken up by plants with the help of mycorrhizae, transferred through food chains, lost from waste product, plants and animals die then broken down by saprobionts releasing ions into the soil and process starts again
What happens during the phosphorus cycle in the sea, lakes and rivers?
phosphate ions released into the sea lakes and rivers by weathering, taken up by aquatic producers e.g algae and passed along food chain, sea birds feed on fish and release waste product called guano which contains high proportion of phosphate ions, used as a fertiliser which returns it back to soil
What is leaching?
When water soluble compounds in soil are washed away by rain or irrigation systems
When is leaching less likely to occur?
Using natural fertilisers
What happens during eutrophication?
Mineral ions are leached from fertilised fields and stimulate rapid growth of algae in ponds and rivers, blocks light reaching plants below, plants die, bacteria feed on dead plants, reduce oxygen concentration by carrying out aerobic respiration, fish and aquatic organisms die due to a lack of oxygen
