Ecology Flashcards
(21 cards)
Population density
the average number of individuals in a population per unit of area or volume.
Dispersion
the dissemination, or scattering, of organisms over periods within a given area or over the Earth.
Density Independent factor
limiting factors that affect the population of organisms but not restricting them to be at or within a certain number, range, or density.
Density Dependent factor
a factor whose effects on the size or growth of a population vary with the population density.
Population growth rate
The annual average rate of change of population size, for a given country, territory, or geographic area, during a specified period.
Emigration
an animal leaves its home because the habitat is no longer ideal for them and they need to find a more suitable environment
Immigration
an animal establishes a home in a habitat because it has resources it can utilize or because the habitat is ideal for them.
Carrying capacity
as a species’ average population size in a particular habitat
Food chain
a linear sequence of organisms through which nutrients and energy pass as one organism eats another
Food Web
consist of many interconnected food chains and are more realistic representation of consumption relationships in ecosystems
Biomass
the mass of living biological organisms in a given area or ecosystem at a given time
matter
anything that occupies space and has mass
Nutrient
substances the body needs for energy, building materials, and control of body processes
Nitrogen Fixation
a biochemical process in which atmospheric N2 is converted into ammonia by certain bacteria (diazotrophs) possessing nitrogenase enzyme
Biogeochemical cycle
describe the movement of chemical elements through different media, such as the atmosphere, soil, rocks, bodies of water, and organisms.
Denitrification
the process by which nitrate is reduced to nitrogen gas by soil microbes when oxygen is not present
Limiting factors
anything that constrains a population’s size and slows or stops it from growing
Ecological succession
the process by which the mix of species and habitat in an area changes over time
Primary succession
happens when a new patch of land is created or exposed for the first time
Climax community
the “endpoint” of succession within the context of a particular climate and geography
Secondary succession
a previously occupied area is re-colonized following a disturbance that kills much or all of its community
