Energy transfer and energy loss Flashcards
What are reasons for which a lot of available energy is never taken in by organisms?
Plants can’t use all the light energy that reaches their leaves (e.g wrong wavelength).
Some parts of food, e.g roots or bones, aren’t eaten by organisms.
Some parts of food are indigestible so pass through organisms and come out as waste, e.g faeces.
What is gross productivity?
The available energy that is absorbed by the body.
What is net productivity?
The amount of energy that’s available to the next trophic level.
Net productivity
= gross productivity - respiratory loss
Efficiency of energy transfer =
net productivity of trophic level/ net productivity of previous trophic level x 100
What is the main route by which energy enters an ecosystem?
Photosynthesis
Name the type of diagram that shows lots of food chains in an ecosystem and how they overlap.
Food web
What is the name given to the amount of energy taken in by an organism?
Gross productivity
What is respiratory loss?
Energy lost to the environment when organisms use energy produced for movement or body heat.
What do pyramids of numbers show?
The number of organisms in each trophic level.
What do pyramids of biomass show?
The amount of biomass in each trophic level.
What is a natural ecosystem?
An ecosystem that hasn’t been changed by human activity.
What is the energy input of a natural ecosystem?
The amount of sunlight captured by the producers in the ecosystem.
What is intensive farming?
Involves changing an ecosystem by controlling the biotic or abiotic conditions.
What different ways can intensive farming methods increase productivity?
They can increase the efficiency of energy conversion- more energy is used for growth and less on other activities e.g recovering from disease or movement.
They can remove growth limiting factors.
They can increase energy input.
In what 3 ways can pests be killed?
Using chemical pesticides.
Using biological agents.
Using integrated systems.
What are herbicides?
Chemical pesticides that kill weeds that compete with agricultural crops for energy.
Reducing competition means crops receive more energy, so they grow faster and become larger, increasing productivity.
What are fungicides?
Chemical pesticides that kill fungal infections that damage agricultural crops.
The crops use more energy for growth and less for fighting infection, so they grow faster and become larger, increasing productivity.
What are insecticides?
These kill pests that eat and damage crops.
Killing pests mean less biomass is lost from crops, so they grow to be larger which means productivity is greater.
What are some environmental issues of using chemical pesticides?
They may directly affect other non pest species, e.g butterflies.
They may indirectly affect other non pest species e.g poisoning secondary consumers.
Give three examples of biological agents.
Natural predators.
Parasites.
Pathogenic bacteria and viruses.
What are some environmental issues of using biological agents?
Natural predators introduced to an ecosystem may become a pest species themselves.
Biological agents can affect other non pest species.
What are some economic issues of using chemical pesticides?
They can be expensive and so may not be profitable for farmers.
What are integrated systems?
Use both chemical and biological.
