C.2 - Communities and Ecosystems Flashcards
Explain how energy is lost in an ecosystem. THERE ARE THREE WAYS.
- energy lost through heat (cell respiration)
- energy that is not consumed will be lost
- energy that is consumed but not assimilated/lost through death
What are the units for energy?
kJ m-2 year-1
What is the formula for gross/net production?
Net production = Gross production - Respiration
Explain what a food conversion ratio is.
The ratio of the amount of food consumed by an animal to the amount of weight gained by the animal over a period of time.
Low FCR = more sustainable
Explain the concept of ecological succession.
The process b y which a sequence of increasingly complex communities develop.
Compare primary and secondary succession.
Primary - when succession begins on a site that has never sustained life before.
Secondary - when succession begins on existing soil following upheaval such as bushfire/land clearing
Outline a typical succession process.
bare rock -> lichens -> moss -> grass and small shrubs -> large shrubs -> fast growing trees -> slow growing trees
Compare and contrast open and closed ecosystems.
OPEN
- all ecosystems are open
- matter and energy is exchanged
CLOSED
- artificial ecosystems
- energy can cross the boundary but matter cannot
Explain how ecosystems can be disturbed.
- change in species diversity
- changes in nutrient cycling
- increased invasive species
- changes to soil biota (the decomposers)
- pesticides can disrupt ecosystems
- changes to salinity
Explain the movement of nutrients in a taiga or temperate forest
- Litter is the main store of nutrients
- Slow transfer of nutrients between stores
Explain the movement of nutrients in a desert
- Soil is the main store of nutrients
- Slow rate of nutrient transfer between stores EXCEPT……..
- Fast transfer from biomass to litter
Explain the movement of nutrients in a tropical forest
- Biomass is the main store of nutrients
- Fast rate of nutrient transfer between stores
