CH 40 FLASH
Terms
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- age structure
- Number of individuals in each age category for a population
- biotic potential
- Of population growth for a given species, the maximum rate of increase per individual under ideal conditions.
- carrying capacity
- The maximum number of individuals in a population (or species) that a given environment can sustain indefinitely.
- cohort
- Group of individuals from a population from the time of birth until the last one dies.
- demographic transition model
- Model that correlates changes in population growth with four stages of economic development.
- demographics
- A population's vital statistics.
- density-dependent control
- Factor that limits population growth by reducing the birth rate or increasing death and dispersal rates (e.g., predation, parasitism, disease, competition).
- density-independent factor
- Factor that causes a population's death rate to rise independently of density (e.g., a severe storm or flood).
- doubling time
- Time it takes for a population to double in size.
- ecology
- [Gk. oikos, home, + logos, reason] The scientific study of how organisms interact with one another and with their environment.
- emigration
- Permanent move by a resident out of a population.
- exponential growth
- Pattern of population growth in which population size expands by ever-increasing increments during successive intervals, because its reproductive base becomes ever larger. Size increases against time plot out as a J-shape curve.
- immigration
- One or more individuals moves from its population and takes up permanent residence in another population of its species.
- J-shaped curve
- Type of diagrammatic curve that emerges when unrestricted exponential growth of a population is plotted against time.
- life history pattern
- Patterns of reproduction, survival, and life expectancy for a population.
- limiting factor
- Single factor that limits the growth, abundance, or distribution of the population of a species in an ecosystem.
- logistic growth
- A population growth pattern. A low-density population slowly increases in size, enters a phase of rapid growth, then levels off in size once the carrying capacity has been reached.
- migration
- Recurring round trip between two or more regions in response to environmental rhythms (e.g., seasonal change).
- net population growth rate per individual (r)
- For population growth equations, a variable combining rates and death rates; assumes that both remain constant in specified interval.
- population density
- Count of individuals of a population in a habitat (by area or volume).
- population distribution
- Dispersal pattern for individuals of a population through a habitat.
- population size
- The number of individuals that make up the gene pool of a population.
- r
- Variable in population growth equations that signifies net population growth rate. Birth and death rates are assumed to remain constant and are combined into this one variable.
- reproductive base
- The number of actually and potentially reproducing individuals in a population.
- S-shaped curve
- Type of diagrammatic curve that emerges when logistic population growth is plotted against time.
- survivorship curve
- Plot of age-specific survival of a group of individuals in the environment, from the time of birth until the last one dies.
- total fertility rate
- (TFR) The average number of children being born to women of a specified population during their reproductive years.
- zero population growth
- Of a population, no overall increase or decrease during a specified interval; population size is stabilized.