27 terms

population growth and regulation

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