The Organism in the EnvironmentEdexcel GCSE Biology: Flashcards
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Four levels of ecological organisation?
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- Four levels of ecological organisation?
- Organism → population → community → ecosystem.
- Define population.
- All organisms of one species in a habitat.
- Define community.
- Populations of different species interacting in a habitat.
- Define ecosystem.
- A community interacting with its abiotic environment.
- Four abiotic factors?
- Temperature, light intensity, water availability, pollutants.
- Two biotic factors?
- Competition and predation.
- What is competition?
- Organisms competing for limited resources.
- Why is interdependence important?
- Removing one species can affect many others, destabilising the community.
- Define parasitism.
- Parasite benefits, host is harmed.
- Define mutualism.
- Both organisms benefit.
- What is a quadrat used for?
- Sampling organism numbers/cover in a known area.
- What is a belt transect used for?
- Sampling species distribution along a gradient.
- Why place quadrats randomly?
- To avoid bias, representative sampling.
- Formula for estimating population size?
- Mean per quadrat × (total area ÷ quadrat area).
- 10 quadrats (1m²) in 200m², mean 3/quadrat. Estimate population.
- 3×200=600.