How is energy transferred to the next trophic level? Flashcards
Is all energy transferred to the next trophic level?
No
What percentage of energy is lost?
90%
What percentage of energy is never taken in?
60%
What is the first reason why 60% of energy isn’t taken in?
Plants can’t use all wavelengths of light
What is the second reason why 60% of energy isn’t taken in?
Some light is reflected and some passes straight through leaves
What is the third reason why 60% of energy isn’t taken in?
Some sunlight is not used because it hits part of the plant that can’t photosynthesis
What is fourth reason why energy isn’t taken in?
Some plants are not eaten so its passed to decomposers
What is the fifth reason why energy isn’t taken in?
Some plants are indigestible so pass through organisms and come out as waste
-Also passes to decomposers
How much of energy is taken in (Gross Productivity)?
40%
How much of the total energy taken in is lost?
30%
How is this 30% of energy lost?
From respiration for movement and body heat (respiration loss)
What happens to the other 10% of energy?
Becomes available biomass (net productivity)
What is the equation of net productivity?
Gross Productivity - Respiratory Loss
What is the equation to calculate the efficiency of energy/biomass transfer between trophic levels?
(energy/biomass in above trophic level ÷ energy/biomass in below trophic level ) x100
How can we calculate the amount of energy in a trophic level?
By measuring the dry mass of organisms
How do we measure the dry mass of the organisms?
1)Calculate the amount of biomass in a sample of organisms
2)Multiply results from sample by size of total population
3)Gives the total amount of energy in the organisms at that trophic level
4)Difference in energy between the levels is the amount of energy transferred
What is the problem with this method?
Consumers may take in energy from other sources
What can human activities increase?
The transfer of energy
What do some farming methods increase?
Productivity by increasing energy transfer
What is the first farming method that increases productivity for plants?
Insecticides kill insects and pests that eat and damage crops
What is the second farming method that increases productivity?
Herbicides kill weeds that compete with crops for energy
What is the third farming method that increases productivity for plants?
Fungicides kill fungal infections that damage crops
What is the fourth farming method that increases productivity for plants?
Introduce natural predators to eat pest species. This means crops lose energy and biomass increasing productivity
What is the fifth farming method that increases productivity for plants?
Fertilisers provide crops with minerals needed for growth. Crops use up minerals as they grow, fertilisers replace these in the soil
What is a farming method that increases productivity for livestock?
Rearing of livestock intensively involved the controlling conditions they live in so more energy is used for growth and less for other activities
What are the two things rearing is able to do?
-Can provide high energy food to increase energy input
-Can keep livestock warm and limit movement so energy is not wasted
What is the benefit of intensive farming?
More food is produced in a short space of time at a lower cost
What is the ethical issue with intensive farming?
Has unnatural conditions and cause pain,distress and increases spread of disease
