6.3 Ecosystems Flashcards
(31 cards)
What is the definition of ecology?
Study of relationships between organisms and the environment
What is the definition of an Ecosystem?
All the living and physical factors of an area
What is the definition of a community?
all the living things in an area/habitat
What is the definition of habitat?
Place where an organism lives
What is a niche?
The role of an organism in the ecosystem
What is a tropic level?
A stage of a food chain
What is the definition of Biomass?
The mass of dry living material in an organism
How do you calculate biomass?
No. Of organisms x biomass of each organism
How is biomass measured?
Organisms are killed and dried out
Only small samples taken to minimise destruction
Therefore value may be unrepresentative
Why is biomass/energy always lower than the previous trophic level?
- Not all organism is eaten
- Not all light energy is used: reflected,wrong wavelength,doesn’t hit chloroplasts
- Some energy used in photosynthesis
- Limiting factors of photosynthesis
- Waste
- Maintaining body temperature
What is the definition of ecology efficiency?
Efficiency with which biomass/energy is transferred from one trophic level to the next
What is the formula for ecological efficiency?
Biomass after transfer/biomass before transfer x 100
How can primary production be improved?
- Fungicides
- Crop rotation
- Herbicides
- Plant crops early
- Temperature control
How can secondary productivity (consumers) be improved?
- Harvest animals prior to adulthood
- Steroids to accelerate growth
- Selective breeding
- Treatment with antibiotics
- Intensive farming
What is the definition of succession?
Process by which ecosystems change over time
What is the definition of primary succession?
Newly formed land
No soil/organic matter present
What is the secondary succession?
- Soil present but no animal/plant species
What is a pioneer community?
- Community which colonise bare land
What are the features of pioneer communities?
- Produce large numbers of seeds/spores
- Seeds that germinate rapidly
- Photosynthesis
- Tolerate extreme environments
- Nitrogen fixing
What is an intermediate community?
- Pioneer species die/decay
- Organic matter released into soil
- Humus added
- New species arrive
- Biodiversity peaks at this stage
What is a climax community?
- Final,stable community
- Very little change over time
What is the definition of phagioclimax?
Deflected succession where the final climax is not reached
Always due to human activity
What is the definition of decomposition?
Chemical process where compounds are broken down into smaller molecules
What is the definition of a limiting factor?
-Environmental resources which limit population growth
