18. organisms and their environment Flashcards
ecology
study of organisms in their environment
habitat
place where an organism lives
community
all of the populations of all of the different species in an ecosystem
ecosystem
a unit containing all of the organisms in a community and their environment interacting together
niche
the role of an organism in its natural environment
foodchain
a diagram showing the flow of energy from one organism to the next, beginning with a producer
food web
a network of interconnected food webs
pyramid of numbers
a diagram in which the area of the bar at each trophic level shows the relative number of organisms at that level in the food chain
pyramid of biomass
a graph showing the relative quantity of biomass at each trophic level
pyramid of energy
a graph showing the relative quantity of energy at each trophic energy
nitrogen fixation
converting inert nitrogen gas into a more reactive form such as nitrate ions or ammonia
nitrification
converting ammonium ions to nitrate ions
denitrification
converting nitrate ions to nitrogen gas
lag phase
the stage at the start of a population growth curve where the population remains small and grows only very slowly
log phase / exponential phase
the stage in a population growth curve where the population grows at its maximum rate so birthrate exceeds death rate
