Ecology Flashcards
What is the source of energy for most living organisms?
Radiation from the Sun
What percentage of the incident energy from light is transferred for photosynthesis?
1%
Where is this incident energy stored?
In the substances that make up the cells of plants
The further up a food chain (trophic level)…
The less energy and less biomass
What do pyramids of biomass show?
The relative mass of living material at a tropic level (i.e. how much all the organisms would “weigh” if you put them all together)
How much of biomass from each trophic level is transferred to the level above it?
Approximately 10%
Why is biomass lost between each trophic level (energy wasted)?
- Organisms don’t eat very single part of organism they’re consuming
- Don’t absorb all stuff in food they ingest (egested as faeces) - lost in organisms’ waste materials
- Some biomass is converted into other substances that are lost as waste
Give an example of some biomass being converted into other substances and that are lost as waste
Organisms use a lot of glucose in respiration to provide energy for movement and keeping warm (rather than make more biomass) + energy from respiration is transferred by heating surroundings
What does respiration produce as waste?
Carbon dioxide and water
Give another example of some biomass being converted into other substances and that are lost as waste (that’s not to do with respiration)
Urea is waste - released in urine with water when proteins in biomass are broken down
How can you calculate the efficiency of a biomass transfer?
Biomass transferred to next level
——————————————————— x 100
Biomass available at the previous level
How can the efficiency of food production be improved?
By reducing the number of stages in a food chain
What does a food chain show?
Shows what’s eaten by what
Plants make glucose by photosynthesis. Some glucose produced is used to make other biological molecules in plant. What are these molecules known as?
The plant’s biomass
What is biomass and what can it be thought as?
It is the mass of living material
Can be thought as energy stored in plant
How is energy is transferred through living organisms in an ecosystem?
By organisms eating other organisms
Populations of prey and predators go in…
cycles
What is the population of any species limited by?
The amount of food available
Explain how populations of prey and predators go in cycles
- If population of prey increases = population of predators will increase
- However, as population of predators increases, number of prey will decrease
Why are predatory-prey cycles always out phase with each other?
Because it takes a while for one population to reasons to changes in other population
E.g. When number of rabbits goes up, number of foxes doesn’t increase immediately because it takes time to reproduce
How can we increase the efficiency in food production? (e.g. with livestock)
- Can limit movement of livestock
- Keep them in a temperature-controlled environment
= reduces transfer of energy from livestock to environment
How does limiting the movement of livestock/controlling the temperature make farming more efficient?
- Animals use less energy moving around & controlling their own body temperature
- Means more energy is available for growth = more food can be produced from same input of resources
What is intensive farming?
Where animals are restricted and kept in confined spaces
Name 3 advantages of intensive farming
- More biomass and energy in animals
- Mass production = more profit
- Free from predators
- Cheaper?