Levels of Organisation in an Ecosystem (OCR GCSE Biology A (Gateway))

Key Terms in Ecology

• There are several key terms that we use when referring to the various different components of an ecosystem and their levels of organisation

• A population is defined as a group of organisms of the same species living in the same place at the same time

• A community includes all of the populations living in the same area at the same time

  • Within a community, each species depends on other species for food, shelter, pollination, seed dispersal etc.

  • If one species is removed it can affect the whole community

  • This is called interdependence

• A habitat is the place where an organism lives

  • eg. badgers, deer, oak trees and ants are all species that would live in a woodland habitat

• An ecosystem is defined as all the biotic factors and all the abiotic factors that interact within an area at one time

  • Biotic factors includes all the living components such as plants and animals

  • Abiotic factors includes all the non-living components such as light intensity, mineral ions, water availability

  • Ecosystems can vary greatly in size and scale

  • A small ecosystem might be a garden pond

  • A large ecosystem might be the whole of Antarctica

Levels of organisation in an ecosystem