Term | Definition |
biosphere | part of earth in which life exists including land, water, and air or atmosphere |
biome | a group of ecosystems that share similar climates and typical organisms |
autotroph | organism that is able to capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds (primary producer) |
detritivore | organism that feeds on plant and animal remains and other dead matter |
primary producer | first producer of energy-rich compounds that are later used by other organisms |
carnivore | organism that obtains energy by eating animals |
heterotroph | organism that obtains food by consuming other living things (consumer) |
chemosynthesis | process in which chemical energy is used to produce carbohydrates |
decomposer | organism that breaks down and obtains energy from dead organic matter |
biomass | total amount of living tissue |
phytoplankton | photosynthetic algae found near the surface of the ocean |
ecological pyramid | illustration of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web |
trophic level | each step in a food chain or food web |
food web | network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem |
zooplankton | small free floating animals that form part of plankton |
biogeochemical cycle | process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another |
nitrogen fixation | process of converting nitrogen gas into nitrogen compounds that plants can absorb and use |
denitrification | process by which bacteria converts nitrates into nitrogen gas |
limiting nutrient | single essential nutrient that limits productivity in an ecosystem |
microclimate | environmental conditions within a small area that differs significantly from the climate of the surrounding area |
greenhouse effect | process in which certain gases trap sunlight energy in Earth's atmosphere as heat |
habitat | area where an organism lives, including the biotic and abiotic factors |
niche | full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions |
resource | any necessity of life, such as water, nutrients, light, food, or space |
competitive exclusion pinciple | principle that states no two species can occupy the same niche in the same habitat at the same time |
predation | interaction in which one organism captures and feeds on another organism |
herbivory | interaction in which one animal feeds on the producer |
keystone species | single species that isnt usually abundant in a community yet exerts strong control on the structure of a community |
symbiosis | relationship in which two species live close together |
mutualism | symbiotic relationship in which both species benefit from the relationship |
parasitism | symbiotic relationship in which one organism lives on or in another organism and harms it |
commensalism | symbiotic relationship in which one organism benefits and the other isnt helped or harmed |
ecological succession | series of gradual changes that occur in a community following a disturbance |
primary succession | succession that occurs in an area in which no trace of a previous community is present |
pioneer species | first species to populate an area during succession |
secondary succession | type of succession that occurs in an area that was only partially destroyed by disturbances |
logistic growth | growh pattern in which a populations growth slows down and then stops following a period of exponentional growth |
exponential growth | growth pattern in which the individuals in a population reproduce at a constant rate |
density dependent limiting factor | limiting factor that depends on population density |
density independent limiting factor | limiting factor that affects all populations in similar ways, regardless of the population density |
demography | scientific study of human populations |