4.2 Energy Transfer, Food Production & Nutrient Cycles Flashcards
What is a biotic component?
A living organism; producers, consumers, saprobionts.
What is an ecosystem?
A natural unit made up of organisms and their interactions with each other + the components (non living) of the habitat
What is an abiotic component?
The physical, non living aspects of the environment such as light, pH, water and CO2
What is biomass?
The total dry mass of organisms
How do we determine biomass?
Heat the plant material, record the mass, repeat until a constant mass is obtained and all water is removed
Why is sunlight conversion to energy low in efficiency?
Light misses the chloroplasts/chlorophyll
Some light is reflected
Light is the wrong wavelength
Why is energy transfer efficiency between trophic levels low?
Heat energy is lost during respiration
Parts of organisms cannot be digested
Loss by excretory products
Equation for efficiency of energy transfer?
Energy avaliable after transfer OVER
Energy avaliable before transfer
X100
=….%
What is Gross Primary Productivity? (GPP)/ Gross Photosynthesis
The total amount of light energy converted to chemical energy in photosynthesis
AKA
how productive photosynthesis is
What js Net Primary Productivity?(NPP) /Net Photosynthesis
The amount of energy from photosynthesis which remains available to primary consumers
How do we find NPP?
NPP= GPP - (R)
(R)= respiratory loss
Why do we need nitrogen in plants?
Essential for the production of amino acids and nucleotides.
What is nitrification?
The oxidation of ammonia and ammonium ions into nitrites and then nitrates by nitrifying bacteria.
How do nitrifying bacteria help plants?
They oxidise the ammonium ions in soil into nitrites and nitrates so that the plant can absorb them by active transport for protein synthesis.
What is ammonification?
The production of ammonia from organic compounds.
What is a saprobiont/ saprobiotic micro-organism?
They cause decay and break down proteins into ammonia to form ammonium ions.
What is denitrification?
The conversion of nitrates into gaseous oxygen by denitrifying bacteria.
Describe the carbon cycle.
Carbon dioxide is removed from the air by plants and used in photosynthesis.
Animals feed on plants to obtain carbon compounds.
Organisms respire 24/7 to release CO2 back.
Saprobionts decompose dead organisms during respiration. They secrete enzymes and carry out extracellular digestion. They absorb soluble products and release CO2.
Where are there fluctuations in CO2 levels?
At night CO2 concentration is greatest as only respiration occurs.
During the day both respiration and photosynthesis occur so the overall photosynthesis rate is greater, so CO2 levels fall.
More leaves carry out photosynthesis at high levels= low CO2
Soil microorganisms and ground animal respiration= higher CO2
How does intensive rearing of domestic livestock maximise yield and energy conversion?
Movement restricted-less energy in muscle contraction
Animals lose less heat in controlled environment- respire less to maintain body temp
Food has high energy content
Predators excluded
Improving yield in domestic livestock?
Growth hormones
Selective breeding
Animals slaughtered before maturity
Antibiotics used to reduce disease
