Key Terms – Population and Community Ecology
- age structure
- the distribution of the proportion of population members in each age class
- birth rate
- the number of births within a population at a specific point in time
- carrying capacity
- the maximum number of individuals of a population that can be supported by the limited resources of a habitat
- climax community
- the final stage of succession, where a stable community is formed by a characteristic assortment of plant and animal species
- competitive exclusion principle
- no two species within a habitat can coexist indefinitely when they compete for the same resources at the same time and place
- death rate
- the number of deaths within a population at a specific point in time
- demography
- the statistical study of changes in populations over time
- density-dependent regulation
- the regulation of population in which birth and death rates are dependent on population size
- density-independent regulation
- the regulation of population in which the death rate is independent of the population size
- environmental disturbance
- a change in the environment caused by natural disasters or human activities
- exponential growth
- an accelerating growth pattern seen in populations where resources are not limiting
- foundation species
- a species which often forms the major structural portion of the habitat
- host
- an organism a parasite lives on
- intraspecific competition
- the competition among members of the same species
- island biogeography
- the study of life on island chains and how their geography interacts with the diversity of species found there
- J-shaped growth curve
- the shape of an exponential growth curve
- K-selected species
- a species suited to stable environments that produce a few, relatively large offspring and provide parental care
- keystone species
- a species whose presence is key to maintaining biodiversity in an ecosystem and to upholding an ecological community’s structure
- life table
- a table showing the life expectancy of a population member based on its age
- logistic growth
- the leveling off of exponential growth due to limiting resources
- mark and recapture
- a method used to determine population size in mobile organisms
- mimicry
- an adaptation in which an organism looks like another organism that is dangerous, toxic, or distasteful to its predators
- mortality rate
- the proportion of population surviving to the beginning of an age interval that dies during that age interval
- mutualism
- a symbiotic relationship between two species where both species benefit
- one-child policy
- a policy in China to limit population growth by limiting urban couples to have only one child or face a penalty of a fine
- parasite
- an organism that uses resources from another species: the host
- pioneer species
- the first species to appear in primary and secondary succession
- population density
- the number of population members divided by the area being measured
- population size
- the number of individuals in a population
- primary succession
- the succession on land that previously has had no life
- quadrat
- a square within which a count of individuals is made that is combined with other such counts to determine population size and density in slow moving or stationary organisms
- r-selected species
- a species suited to changing environments that produce many offspring and provide little or no parental care
- relative species abundance
- the absolute population size of a particular species relative to the population size of other species within the community
- S-shaped growth curve
- the shape of a logistic growth curve
- secondary succession
- the succession in response to environmental disturbances that move a community away from its equilibrium
- species distribution pattern
- the distribution of individuals within a habitat at a given point in time
- species richness
- the number of different species in a community
- survivorship curve
- a graph of the number of surviving population members versus the relative age of the member
- zero population growth
- the steady population size where birth rates and death rates are equal