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Biology II Chapter 16 Vocab

Terms in this set (20)

population
consists of all the individuals of a species that live together in one place at one time.
Population size
the number of individuals in a population
Population density
the number of individuals that live in a given area
Dispersion
he way the individuals of the population are arranged in space
Population model
a hypothetical population that attempts to exhibit the key characteristics of a real population.
exponential growth curve
a curve in which the rate of population growth stays the same, as a result the population size increases steadily.
carrying capacity
the population size that an environment can sustain
Density dependent factors
factors that at which the rate becomes depleted depends upon the population density of the population that uses them.
Logistic model
a population model in which exponential growth is limited by a density dependent factor.
Density independent factors
environmental conditions that can limit growth
R strategists
species that grow exponentially when environmental conditions allow them to reproduce.
K strategists
their population density is usually near the carrying capacity of their environment. Species that grow slowly
Hardy Weinberg principle
states that the frequencies of alleles in a population do not change unless evolutionary forces act on the population.
Gene flow
the movement of alleles into or out a population
Nonrandom mating
when individuals prefer to mate with others that live nearby or are of their own phenotype.
Genetic drift
the change in allele frequencies that appears to occur randomly, as if the frequency were drifting.
Polygenic trait
a trait that is influenced by several genes
Normal distribution
a hill shaped curve on a graph with the average at the summit
directional selection
the form of selection that causes the frequency of a particular trait to move in one direction
stabilizing selection
the distribution becomes narrower, tending to stabilize the average by increasing the proportion of similar individuals.
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