Species
A group of actually or potentially interbreeding organisms, with a common gene pool, which are reproductively isolated from other such groups
Habitat
The environment in which the species lives
Population
A group of organisms of the same species that live in the same area at the same time and can produce fertile offspring
Community
A group of populations living and interacting in an area
Ecosystem
Contains a community (biotic) and non-living (abiotic) parts of the environment
Ecology
The study of interactions of organisms with one another and with their environment
Autotrophs
Producers that make their own food through photosynthesis; they begin food chains
Heterotrophs
Organisms that, instead of making their own food, rely on ingesting other organisms
Consumers
Organisms that ingest organic matter that is living or recently killed
Detritivores
Organisms that ingest dead organic matter
Saprotrophs
Organisms that live on or in dead organic matter, secreting enzymes into it and absorbing the products of digestion
Trophic Level
An organism's position in the food chain
Competition
When two or more species compete for a particular resource
Herbivory
A primary consumer feeding on a plant or its products
Predation
A predator killing its prey
Parasitism
A relationship between two different species where only one species benefits and the other is usually harmed
Mutualism
Between two different species where both species have some degree of physiological dependency on one another and benefit from the relationship
Fundamental Niche
The niche that an organism could potentially occupy, given the adaptations of the species
Realized Niche
The proportion of the fundamental niche that is actually occupied by the organism which results from its adaptations and competition from other species
Biomass
The total dry mass of organic matter in organisms or ecosystems
Gross Production
The total amount of organic matter produced by plants in an ecosystem
Net Production
The amount of gross production in an ecosystem remaining after subtracting the amount used by plants in respiration
Primary Succession
When life starts in an environment where living organisms have not previously existed
Secondary Succession
Occurs in an area where an ecosystem is present but is replaced by other ecosystems because of change in conditions
Biome
A large geographical area that has a certain kind of climate and sustains a specific community of plants and animals
Biosphere
The total of all areas where living things are found, including deep ocean and the lower part of the atmosphere
Biomagnification
A process in which chemical substances become more concentrated at each trophic level