ECOLOGICAL EFFICIENCY Flashcards
What do the animals use their energy from food to do?
Carry out the processes essential to keep them alive.
What is secondary production?
Using energy to make organic materials for the growth of the animal.
How much of the digested food is converted into biomass?
Little
What happens to food that is indigestible?
It is passed through the digestive system to be egested as faeces.
What happens to food material that is digested and absorbed?
Mainly used for respiration, so a great deal of energy is lost from the animal as heat and movement
Why do homeotherms (birds and mammals) have less energy for secondary production?
Because they use a lot of their energy to regulate their body temperature and so have less energy for secondary production.
Why do poikilotherms (invertebrates and fish) have more energy available for growth?
They do not use energy from their metabolism to regulate their body temperature.
Why is the energy flow in a food web immensely complex?
Because most animals feed on a very wide range of food sources.
What are the main reasons why there are significant losses of energy at each transfer from one trophic level to the next?
Only a small fraction of the energy taken in by an animal becomes secondary production, most of the energy is lost as heat and movement or simply not available because the food could not be digested.
What is ecological efficiency?
The term used to describe the proportion of energy taken in by one trophic level that is converted into new biomass and so is available to the next trophic level.
What happens to undigested materials?
They pass into the faeces
What is the organic material available in faeces a food source for?
Saprotrophs
What do saprotrophs use the food for?
Biomass production. Eventually the energy will be used for respiration and lost as heat and movement.
What do pyramids of energy flow show?
energy built into biomass at each trophic level in a unit area in a year
Why does each level of the pyramid get smaller?
Because there is less energy available for production for the next trophic level due to losses as heat and movement.
