5.2.3Unit 5: Respiration, Internal Environment, Coordination and Gene Technology
Ecology: Key Terms — IAL Edexcel Linear Revision Notes & Topical Questions
5 min read 5 parts Lesson 18 of 36 Unit quiz
Part 1 of 5Levels of Organisation
Ecology is studied at several scales, from individuals up to the whole ecosystem.
1
A species is a group of organisms that can interbreed to produce fertile offspring.
2
A population is all the individuals of one species living in a habitat at the same time.
3
A community is all the populations of different species living in one habitat.
4
An ecosystem is the community together with the abiotic factors, such as light, temperature and water, in the same area.
5
Large ecosystems with a similar climate, such as tundra or rainforest, are called biomes.
Part 2 of 5Factors
Habitat
- The place where an organism lives, such as a pond or woodland floor.
Biotic factor
- A living factor such as predation, competition or disease.
Abiotic factor
- A non-living factor such as temperature, pH, light or salinity.
Niche
- The role of a species within its ecosystem, including what it eats and where it lives.
Interaction
- Biotic and abiotic factors affect each other, for example plants altering soil moisture.
Part 3 of 5Feeding Roles
Feeding Roles
Producer
- An autotroph that makes organic molecules by photosynthesis.
Consumer
- A heterotroph that gets energy by eating other organisms.
Decomposer
- Feeds on dead organisms and waste and releases nutrients.
Trophic level
- A feeding position in a food chain, such as primary consumer.
Part 4 of 5Describing Populations
Abundance
- The number of individuals of a species in a habitat.
Distribution
- Where in the habitat the species is found.
Carrying capacity
- The maximum population size that the environment can support indefinitely.
Biodiversity
- The variety of living organisms in an area.
| Term | Example |
|---|---|
| Population | All the frogs in a pond |
| Community | All the species in the pond |
| Ecosystem | The pond and its light, water and sediments |
Part 5 of 5Exam Checklist & Tips
5.2.3 – Key Points for the Exam
- Ecosystem A community of organisms together with their non-living environment.
- Habitat The place where an organism lives.
- Population All the members of one species in a habitat.
- Community All the populations of different species in a habitat.
- Niche The role of an organism in its ecosystem.
Common Mistakes
- Using habitat and niche as if they mean the same thing; habitat is where, niche is the role.
- Describing a population as including several species.
- Calling an ecosystem only the living organisms and leaving out abiotic factors.
- Mixing up abundance, how many, with distribution, where.
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