GCE O Level Biology: Definitions of Keywords from Ecology & Impact of Human Activities on the Ecosystem

Habitat
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Terms in this set (21)
Habitat
Place where an organism lives and carries out all its activities such as feeding and reproduction
Image: Habitat
Population
Group of organisms of the same species living and reproducing in a particular habitat
Community
All populations of organisms living and interacting with one another under the same environmental conditions
Image: Community
Ecosystem
Formed by the interaction between communities of living organisms and their abiotic environment
Image: Ecosystem
Producers
Mainly green plants that can convert light energy into chemical energy in the form of glucose through photosynthesis
Image: Producers
Consumers
Organisms which obtain their energy and nutrients from the organisms they feed on
Image: Consumers
Decomposers
Organisms feeding on and breaking down dead organisms as well as waste matter into simple inorganic substances which are returned to the non-living environment
Image: Decomposers
Food chain
A series of organisms through which energy is transferred in the form of food from organism to organism along a feeding pathway
Image: Food chain
Food web
Complex feeding relationship in a community where two or more food chains are linked together
Image: Food web
Trophic level
A feeding stage in a food chain
Image: Trophic level
Pyramid of numbersRepresents the number of organisms present in each trophic level of a food chain at a particular timePyramid of biomassRepresents the total dry mass of organisms present in each trophic level at a particular timePyramid of energyRepresents the rate of energy flow in a food chain over a period of timeDeforestationClearing of large areas of forestsEutrophicationProcess in which a body of water is polluted with an abundant supply of sewage or fertilisers, resulting in an accelerated algal growthBioaccumulationA build-up of non-biodegradable chemicals, such as pesticides, within an organism as the chemical is absorbed faster than it can be removedBioamplificationAn increase in the concentration of non-biodegradable chemicals, such as pesticides, along a food chainConservationThe protection and preservation of natural resources in the environmentBiodiversityRange of species that are present in a particular ecosystemReforestationPlanting of forests to replace trees that have been removed or destroyedCarbon sinkAnything that absorbs carbon dioxide more than it releases