27 terms

age structure

the distribution of individuals among age classes within a population

carrying capacity

the number of individuals in a population that the resources of a habitat can support

cohort life table

a life table follows the fates of a group of individuals born into a population at the same time from their birth to the death of the last individual

continuous time approach

an approach to pop. modeling assuming that time flows continuously and that change can occur at every instant.

demography

the study of the structure and growth of populations

density dependent

having an influence on a population that varies with the size of the population

density independent

having an influence on a population that does not vary with the size of the population

discrete time approach

an approach to pop. modeling that uses discrete time intervals between reproductive periods

doubling time

the time required for a population to grow to twice its size

exponential growth

continuous increase or decrease in a population at a rate that is proportional to the number of individuals at a given time

fecundity

the number of offspring produced per reproductive episode

generation time

the average period between the birth of an individual and the birth of its offspring

geometric growth

increase or decrease in pop. as measured over discrete intervals in which the increment is proportional to the # of individuals at the beginning of the interval

inflection point

the point at which a logistic or other sigmoid growth curve changes from its accelerating to its decelerating phase (N = K/2)

intrinsic rate of increase

the growth rate of a population with a stable age distribution

logistic equation

the mathematical expression of an exponential rate of population increase that decreases in linear fashion as population size increases

negative density dependence

a population response to increasing density that depresses survival and birth rates

net reproductive rate

the number of female offspring produced by an average female during her lifetime

per capita

expressed on a per individual basis

positive density dependence

a population respons to increasing density that increases survival and birth rates (inverse)

recruitment

addition of new individuals to the breeding population by reproduction

self-thinning curve

a characteristic relationship between average plant weight and pop. density found in plant pop that are limited by space or other resources

stable age distribution

the proportions of individuals in various age classes in a population that is growing at a constant rate

stable life table

a life table that follows individuals of various age classes within a pop. over a given time interval (time specific )

survival

the probability of an individual living from one age or time period (x) to the next

survivorship

the probability that a newborn individual will be alive at age x

-3/2 power law

a generalization proposing that the relationship between the logarithms of the biomass and the density of a plant population has a slope of -3/2