30 terms


Limiting factor
factor that causes the growth of a population to decrease
Role or position a species has in its environment; includes all biotic and abiotic interactions as an animal meets its needs for survival and reproduction
group of individuals of the same species that live in the same area
all the different populations that live together in an area
collection of all the organisms that live in a particular place, together with their nonliving (abiotic) environment
an organism that makes its own food
Primary consumer
an organism that eats producers
Secondary consumer
An organism that eats primary consumers
Tertiary consumer
an organism that eats secondary consumers
Trophic level
each step in a food chain or food web
Food web
(ecology) a community of organisms where there are several interrelated food chains
Food chain
a series of steps in which organisms transfer energy by eating and being eaten
symbiotic relationship in which both species benefit from the relationship
symbiotic relationship in which one member of the association benefits and the other is neither helped nor harmed
symbiotic relationship in which one organism lives in or on another organism (the host) and consequently harms it.
organism that breaks down and obtains energy from dead organic matter
Exponential growth
growth pattern in which the individuals in a population reproduce at a constant rate
J-shaped graph
graph of exponential growth
Logistical growth
Population growth pattern that begins with rapid growth, and slows down as the environmental carrying capacity is reached; characterized by an S-shaped curve when graphed.
a natural community of plants and animals, its composition being largely determined by climatic conditions.
Biogeochemical cycle
the exchange of matter through the biosphere
orderly natural changes and species replacements that take place in communities and ecosystems over time
Primary succesion
succesion that occurs on land where no soil exists
Secondary succession
succession following a disturbance that destroys a community without destroying the soil
Pioneer species
First species to populate an area during succession
organism that obtains energy from the foods it consumes; also called a consumer
Algal bloom
an immediate increase in the amount of algae and other producers that results from a large input of a limiting nutrient
Pyramid of energy
an ecological pyramid that shows the energy flow through each trophic level in an ecosystem (10%)
Pyramid of biomass
illustrates the relative amount of living organic matter available at each trophic level in an ecosystem
the dry weight of organic matter composing an organism or trophic level in a particular habitat