6.3 Ecosystems, Populations and Sustainability Flashcards
What are some biotic factors experienced by a rock pool?
- Food competition
What are some abiotic factors experienced by a rock pool?
- Tides: pH, salinity, temperature
What are some biotic factors experienced by a playing field?
- Food
What are some abiotic factors experienced by a playing field?
- Rainfall
- Sunlight
What are some biotic factors experienced by a large tree?
- Deformation (removal of leaves)
What are some abiotic factors that can be experienced by large trees?
- Low rainfall
What is the main way that energy enters an ecosystem?
Through photosynthesis
What do plants store energy as?
Biomass
What is biomass?
The mass of living material
How is energy transferred through the living organisms of an ecosystem?
By the organisms eating other organisms
What do food chains and webs show?
How energy is transferred through an ecosystem
Why isn’t all energy transferred to the next trophic level?
Because around 90%of available energy is lost in various ways
How is energy lost in trophic levels?
- some energy isn’t taken in
- Some energy is lost via respiration
Why is some of the available energy not taken in by organisms?
- Plants can’t use all the light energy that reaches their leaves. Some is the wrong wavelength, some is reflected, and some passes straight through the leaves.
- Some sunlight can’t be used because it hits parts of the plant that can’t photosynthesise I.e the bark.
- Some parts of food aren’t eaten by organisms so the energy isn’t taken in
- Some parts of food are indigestible so pass through organisms and come out as waste
What is the net productivity?
The amount of energy that is available for the next trophic level
What is the gross productivity?
The energy that is taken in
Net productivity =
Gross productivity- respiratory loss
Efficiency =
Biomass transferred/ biomass intake X 100
What is the carbon cycle?
How carbon moves through living organisms and the non-living environment
Give the 8 stages of the carbon cycle
1) Photosynthesis
2) Respiration by plants
3) Feeding
4) Death and waste
5) Respiration by animals
6) Decomposition of dead animals
7) No Decomposition after death , leading to the formation of fossil fuels.
8) Combustion of fossil fuels
What is called when decompsoers feed on dead organic matter?
Saprobiontic nutrition
What are rocks such as limestone and chalk mainly composed of ?
Calcium carbonate
what do plants and animals need nitrogen to make?
proteins and nucleic acids
what does the nitrogen cycle show?
how nitrogen is converted into a useable form and then passed on between different living organisms and the non-living environment
What are the 4 main processes of the nitrogen cycle?
- Nitrogen fixation
- Ammonification
- Nitrification
- Denitrification
what is nitrogen fixation?
where nitrogen gas is turned into Ammonium(NH4+) by bacteria Rhizobium and Azotobacter
where is rhizobium found?
in root nodules of legumous plants