Biology - Ecology

biosphere

part of Earth in which life exists including land, water, and air or atmosphere

species

group of similar organisms that can breed and produce fertile offspring

population

group of individuals of the same species that live in the same area

community

assemblage of different populations that live together in a defined area

ecology

scientific study of interactions among organisms and between organisms and their environment

ecosystem

all the organisms that live in a place, together with their nonliving environment

biome

group of land ecosystems with similar climates and typical organisms

biotic factor

any living part of the environment with which an organism might interact

abiotic factor

physical, or nonliving, factor that shapes an ecosystem

autotroph

organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds

primary producer

first producer of energy-rich compounds that are later used by other organisms

photosynthesis

process used plants and other autotrophs to capture light energy and use it to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates such as sugars and starches

chemosynthesis

process in which chemical energy is used to produce carbohydrates

heterotroph

organism that obtains food by consuming other organisms

consumer

organism that relies on other organisms for its energy and food supply

carnivore

organism that obtains energy by eating animals

herbivore

organism that obtains energy by eating only plants

scavenger

animal that consumes the carcasses of other animals

omnivore

organism that obtains energy by eating both plants and animals

decomposer

organism that breaks down and obtains energy from dead organic matter

detritivore

organism that feeds on plant and animal remains and other dead matter

food chain

series of steps in an ecosystem in which organisms transfer energy by eating and being eaten

food web

network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem

trophic level

each step in a food chain or food web

ecological pyramid

illustration of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web

biomass

total amount of living tissue within a given trophic level

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

limiting nutrient

single essential nutrient that limits productivity in an ecosystem