Flash Cards

Ecology of Ecosystems

Term Definition
Ecosystem A community of organisms interacting within a particular physical environment or a community plus its abiotic factors.
Photoautotrophs Organisms that carry out photosynthesis–primarily plants
Autotrophs Primary producers
Consumers Organisms that consume primary producers
Herbivores Consumers which eat plants
Carnivores Consumers which eat animals
Omnivores Organisms which eat both plants and animals
Decomposers Organisms which obtain their energy by breaking down the remains or products of organisms (includes fungi and bacteria)
• Detritivores Decomposers which eat detritus (organic waste and dead organisms)
Detritus Organic wastes and dead organisms
Trophic Feeding
• First trophic level Contains the autotrophs which build energy containing molecules. (They also absorb nitrogen, phosphorous, sulfur and other molecules necessary for life)
• Chemoautotrophs An organism that manufactures its own food through chemosynthesis (the oxidation of inorganic chemical compounds) as opposed to photosynthesis. Bacteria
• Second trophic level Contains the primary consumers which eat the primary producers including herbivores, decomposers and detritivores, e.g. insects, grasshoppers, deer and wildebeest
• Third trophic level Contains the secondary consumers, primary carnivores which eat the herbivores, e.g. mice, spiders and many birds
• Fourth trophic level Contains the tertiary consumers, secondary carnivores who eat the primary carnivores, e.g. weasel, owl, sharks and wolves.
Food webs Intricate pathways of energy flow and material cycling
• Gross primary productivity The rate at which the primary producers capture and store energy per unit time.
Biological magnification The tendency for toxic substances to increase in concentration at progressively higher levels of the food chain

Ecological succession A directional, cumulative change in the species that occupy a given area, through time
• Primary succession Starts from barren ground, e.g. new islands or de-glaciated areas
• Secondary succession Starts from disturbed areas, e.g. abandoned farm land or storm ravaged land
Pioneer community The first organisms to occupy an area
Transitional communities Communities may come and go
Climax community A stable, self-perpetuating array of species in equilibrium with one another and their habitat
Biodiversity Biodiversity, the number of different species within an area
• Biome A large region of land characterized by the climax vegetation of the ecosystems within its boundaries
• Weather The condition of the atmosphere at any given time
• Climate The accumulation of weather events over a long period of time (temperatures, humidity, wind, cloud cover, rainfall)
• Climate is dependent upon several factors: Solar radiation
The earth's daily rotation
The earth's rotation around the sun
The distributions of continents and oceans

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