Basic ecological terms
Ecology is the study of relationships between organisms and their environment. A habitat is the place where an organism lives. An ecosystem includes the living community and the non-living factors interacting in a particular area. A niche is the role of an organism in its habitat.
Levels of organisation
An individual belongs to a population, populations form a community, and a community together with its physical environment forms an ecosystem. The biosphere includes all regions of Earth where life exists.
Feeding relationships
A food chain shows the transfer of energy from producers to consumers. A food web links several food chains. Producers make organic food, primary consumers feed on producers, and higher consumers feed on other consumers. Decomposers break down dead material and return nutrients to the environment.
Cycles and succession
The water, carbon, nitrogen, and phosphorus cycles move essential substances through organisms and the environment. Ecological succession is the gradual change in a community over time. Primary succession begins where no soil exists, while secondary succession begins where a previous community has been disturbed but soil remains.
Biomes and human impact
Biomes are large ecological regions influenced by climate. Human activities such as deforestation, overgrazing, pollution, mining, and urbanisation can reduce biodiversity and disrupt energy flow and nutrient cycles.
Revision questions
- Define habitat, ecosystem, and niche.
- Distinguish between a food chain and food web.
- What is the role of decomposers?
- Compare primary and secondary succession.
