Community - All the organisms living in one easily defined area.
Habitat - The place where an organism lives.
Population - All the organism belonging to the same species living in the same area at the same time. Males and females within the population can inerbreed.
Niche - The role of the species in a comminity (position in the food chain and the intereactions it has with other species).
Ecosystem - A self - contained community together with all the physical features that influence the community. The interactions between orgainsms and their environment.
Producer - An organism that converts simple inorganic molecules into complex organic compounds. Most use light to provide the energy to drive the reactions involved.
Consumer - An organism that gain energy from complex organic matter.
Decomposer - An organism that feeds on waste from other organisms, or on dead organisms.
Trophic Level - Each feeding leve in a food chain.
Primary Succession - The changes that result when the starting point is bare, uncolonised land. e.g. samd dunes, lava, lanslides, retreating glaciers.
Secondary Succession - when an established communtiy is destroyed and a new community develops.
Climax Community - The final, stable community that results after succession. The species of a climax community:
- have large seeds(with large energy store) so seedling can survive low light intensity.
- have a specialised niche.
- are unable to tolerate great lfuctuations in water content of soil.
- are strongly influenced by other organisms.
Pioneer Species - The early arrivals to a habitat experiencing succession:
- are able to tolerate extreme conditions.
- have very good means of dispersal, usually by wind.
- are not able to compete for resources.
- not influenced by or dependant on animal species.
- may be able to fix nitrogen and build up soil nutrients.
Decomposers - organisms that feed on waste from other organisms or on dead organisms.
Nitrogen Fixation - The conversion of nitrogen gas into a form usable by plants, such as nitrate or ammonium ions.
Carrying capacity - the maximum population denisty that can be supported by permanantly in its habitat.
Density-dependant limiting factors have a proportional increase or decreases in their effect as the population density rises or falls.
Biotic - caused by other living things. e.g. predation of infection by pathogens.
Abiotic - inloving non-living components of the environment. e.g. water supply.
Intraspecific Competition - between members of the same species.
Interspecific Competetion - between memebers of different species.
Competitive Exclusion - As a result of competition, 2 species will not occupy the same niche. One will displace the other so each adopts a certain way of life in which it has an advantage.
Conservation - may be needed to protect a species, habitat or ecosystem because it is at risk from human influence or other pressures. Includes the active management needed to maintain or increase biodiveristy.
Preservation - protects species and/or habitats for example by creating a nature reserve.
Sustainable Management - allows an economically important resource to be exploited indefinatlely.