Biology · OCR Paper 2
Communities in Ecosystems
How living things are organised into organisms, populations, communities and ecosystems, how abiotic and biotic factors affect communities, how interdependence and competition work, and how trophic levels, pyramids of biomass and the efficiency of biomass transfers describe the feeding relationships in a community. Matches OCR GCSE Biology A (Gateway Science) B4.1e to B4.1j. The first three lessons are for both Combined Science and separate Biology. Trophic levels, pyramids of biomass and the efficiency of biomass transfers (B4.1h to B4.1j) are for separate Biology only. Nothing in this chapter is for the Higher tier only.
Lessons
Ticks are remembered on this device only.
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1
Levels of Organisation in an Ecosystem
Living things do not live alone. This lesson describes the different levels of organisation in an ecosystem, from a single organism up to the whole ecosystem…
8 terms -
2
Abiotic and Biotic Factors
Where an organism lives, and how many of them there are, depends on its surroundings. This lesson explains how abiotic factors such as temperature, light…
8 terms -
3
Interdependence and Competition
No species lives alone. This lesson explains how living things depend on each other, through predation, mutualism and parasitism, how they compete for…
8 terms -
4
Trophic Levels, Pyramids of Biomass and Efficiency
Energy and biomass flow through a community along food chains. This lesson is for separate Biology. It describes the trophic levels in a food chain, shows how…
8 terms
Key terms in this chapter
All 32, gathered from every lesson.
- Organism
- A single living thing.
- Species
- A group of similar organisms that can breed together to produce fertile offspring.
- Population
- All the organisms of one species in an area.
- Community
- All the populations of different species in an area.
- Ecosystem
- A community and its non-living surroundings.
- Habitat
- The place where an organism lives.
- Abiotic factor
- A non-living part of the environment.
- Biotic factor
- A living part of the environment.
- Abiotic factor
- A non-living factor that affects organisms, such as temperature.
- Biotic factor
- A living factor that affects organisms, such as a predator.
- Light intensity
- How bright the light is.
- Moisture level
- How much water there is in the soil or the environment.
- Soil pH
- How acidic or alkaline the soil is.
- Quadrat
- A square frame used to sample the organisms in an area.
- Transect
- A line along which samples are taken, to see how species change across a habitat.
- Predator
- An animal that hunts and eats other animals.
- Interdependence
- The way in which species in a community depend on each other.
- Predation
- The hunting and eating of one animal by another.
- Mutualism
- An interaction in which both organisms benefit.
- Parasitism
- An interaction in which a parasite lives on or in a host and harms it.
- Competition
- The struggle between organisms for the same limited resource.
- Predator
- An animal that hunts and eats other animals.
- Prey
- An animal that is eaten by a predator.
- Stable community
- A community in which the populations stay fairly constant.
- Trophic level
- The position of an organism in a food chain.
- Producer
- An organism that makes its own food, such as a plant.
- Primary consumer
- An animal that eats producers.
- Secondary consumer
- An animal that eats primary consumers.
- Tertiary consumer
- An animal that eats secondary consumers.
- Pyramid of biomass
- A diagram that shows the mass of living material at each trophic level.
- Egestion
- The loss of undigested food as faeces.
- Efficiency
- The percentage of the biomass at one level that is transferred to the next.