populations Flashcards
Population size
the number of individuals in the population
Population density
the individuals that live in a given area (pop size divided by the area)
Growth rate
birth rate minus death rate
Dispersion
the way individuals of a population are arranged in space
Three types of dispersion?
Uniform, random, clumped
Density-dependent factors
limited resources; rates of depletion depend on the density of the population using them
Density-independent factors
factors unaffected by density that affect the growth of populations (e.g., climate, geography)
Carrying capacity (k)
the number of individuals in a population that an
environment can sustain
Population models
hypothetical populations that attempt to exhibit the key characteristics of a real population (often mathematical)
Exponential model
“J” shaped curved showing a rapid increase in population side
Logistic model
the population model in which exponential growth is limited by density-dependent factors (causing an “S” curve)
r-strategists
an opportunistic population; population density fluctuates; usually in open habitats with little competition
k-strategists
a population in equilibrium; its density hover near the carrying capacity
