Key Terms in Ecology (SQA National 5 Biology): Revision Note

Ecological terms

• Ecology is the study of the relationships between organisms and their environment

• The field of ecology uses specific ecological key terms, e.g. when describing:

  • species in their environment

  • food chains and food webs

Species in their environment

• A species can be defined as:

a group of similar organisms that can interbreed to produce fertile offspring

• Members of one species that live together in an area at a given time are known as a population

• The variety of different species living in an area is known as biodiversity; this can be assessed at the level of an individual habitat, or the earth as a whole

Food chains and food webs

• Food chains shows how energy is transferred from one organism to another in a sequence of feeding relationships, while food webs are networks of interconnected food chains

• The organisms within food chains and food webs can be referred to using terms such as:

  • producer: an organism that makes its own biological molecules, e.g. during photosynthesis

  • consumer: an organism that gains its biological molecules by eating the tissues of other organisms

  • herbivore: a consumer that eats plants

  • carnivore: a consumer that eats other animals

  • omnivore: a consumer that eats both plants and animals

  • predator: an animal that hunts and kills other animals for food

  • prey: an animal that is hunted and eaten by a predator

• For example, a food chain may contain: grass → mouse → owl

• In this food chain:

  • the grass is a producer

  • the mouse is a consumer, a herbivore and a prey animal

    • Mice are actually omnivores, but this is not shown in the food chain described above

  • the owl is a consumer, a carnivore and a predator