chap.16 key terms
Terms
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- groupe of individuals that belong to the same species, live in the same area, and breed with others in the group
- population
- total number of individuals in a population
- population size
- in a population, the number of indviduals in a given area
- population density
- the pattern of distribution of distribution of organisms in a population
- dispersion
- hypothetical population that attempts to exhibit the key charachteristics of a real population
- population model
- J-shaped curve showing the rapid increase in an exponentially growing population
- exponenetial growth curve
- population size that an evironment can sustain
- carrying capacity
- limited resources whose ratesof depletion depend on the density of the population using them
- density-dependent factor
- model of population growth that assumes finite resource levels limit population growth
- logistic model
- factors, such as climate, that affect the grwoth of population. these factors are unaffected by the density of population
- density-independent factor
- species characterized by rapid growth, high gertility, short lifespan and exponenetial population growth
- r-strategist
- species characterized by shlow maturation, few youg, slow popoulation growth and reprodcuion late in life
- k-strategist
- principle stating that the frequency of alleles in a population does not chage unless evolutionary forces act on the population
- Hardy-Weinberg principle
- movement of alleles into or out of a population due to the migration of individuals to or from the population
- gene flow
- mating between individuuals of the same phenotype or by those who live nearby
- nonrandom mating
- random change in allele frequency in a population
- genetic drift
- characteristic of an organism that is influenced by several genes
- polygenic trait
- bell-shaped curve that results when the values of a trait in a population are plotted agaisnt their frequency
- normal distribution
- natural selection that causes the frequency of a particular allele to move in one direction
- directional selection
- type of natural selection in which the average form of the trait is favored and becomes more common
- stabilizing selection