Ecology definitions

Ecology is the study of the interaction between organisms and their environment.

BiodiversityThe variety of different species present in the community of an ecosystem
BiomeRegions of the planet which are characterised by their climate and contains distinctive communities of plants and animals
CommunityAll the organisms present in an ecosystem
EcosystemAll the organisms living in a particular area and the non-living components that the organisms interact with
HabitatThe place where an organism lives
PopulationAll the organisms of one species found in a particular area
SpeciesA group of organisms capable of breeding with each other to produce fertile offspring

Feeding relationships in ecosystems

All organisms require an energy supply for cell activities such as growth and cell division.

Organisms release energy from their food by the process of respiration. In most ecosystems on the planet the ultimate source of energy is the sun.

Producers make their own food using light energy from the sun. Green plants produce their own food by carrying out photosynthesis using light energy from the sun. Consumers cannot make their own food and obtain their energy by eating other organisms.

The feeding relationships that exist in an ecosystem can be shown by a food chain.

Feeding relationships in ecosystems, demonstrated by a food pyramid with 4 tiers, the widest at the bottom and the narrowest at the top.  Tier 1 at bottom, is the producer, represented by plants.  Tier 2 is the primary consumer, represented by a snail. Tier 3 is the secondary consumer represented by a frog and tier 4 is the tertiary consumer represented by a fox.

The arrows represent the flow of energy and mean 'gets eaten by'.

The feeding relationships in most ecosystems are more complicated than simple food chains. Producers are consumed by a range of different animals and these primary consumers may be eaten by a range of different secondary consumers.

The various interconnecting food chains in an ecosystem make up the food web.

The diagram below is an example of part of a food web in a Scottish loch.

A food web of a Scottish loch. At the bottom are algae on stones and floating algae.   Algae on stones is consumed by snails and tadpoles.  Floating algae is consumed by mosquito larvae and water fleas.  Ducks consume the snails and mosquito larvae.  Tadpoles are consumed by dragonlfy larvae which also eat the water fleas.   Water fleas are also consumed by minnows.