Chapter 16
Terms
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- exponential growth curve
- a curve in which the rate of population growth stays the same, as a result the population size increases steadily.
- R strategists
- species that grow exponentially when environmental conditions allow them to reproduce.
- dispersion
- the way the individuals of the population are arranged in space.
- nonrandom mating
- mating between individuals of the same phenotype, or by those who live nearby.
- density- independent factors
- factors, such as climate, that affect the growth of populations. These factors are unaffected by the density of populations.
- stabilizing selection
- type of natural selection in which the average for of the trait is favored and becomes more common.
- population model
- a hypothetical population that attempts to exhibit the key characteristics of a real population.
- gene flow
- the movement of alleles into or out of a population.
- logistic model
- a population model in which exponential growth is limited by a density-dependent factor.
- carrying capacity
- the population size that an environment can sustain.
- K strategists
- populations that grow slowly, slow maturation, few young, slow population growth, and reproduction late in life.
- directional selection
- the form of selection that causes the frequency of a particular trait to move in one direction.
- population density
- the number of individuals that live in a given area
- normal distribution
- bell shaped curve that results when the values of a trait in a population are plotted against their frequency.
- polygenic trait
- a trait that is influenced by several genes.
- genetic drift
- random change in allele frequency in a population.
- Population size
- the number of individuals in a population
- population
- all the individuals of a species that live together in one place at one time.
- Hardy-Weinberg principle
- states that the frequencies of alleles in a population do not change unless evolutionary forces act on the population.
- density dependent factors
- - limited resources whose rates of depletion depend on the density of the population using them.