ch. 20
Terms
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- logistic model
- population growth builds on the exponentail model but acocunts for the influence of limiting factors
- immigration
- the movement of individuals into a population
- hunter-gatherer lifestyle
- a time period when humans lived in small nomadic groups and otained food by hunting animals and gathering berries,roots shellfish and fruits
- logistic growth
- when a population size is at its carrying capacity, the birth rate equals the death rate and the growth stops
- density-dependent factors
- resource limitations like shortages are triggered by increasing popualtion density
- density-independent factors
- reduces the population by the same proportion regardless of the populations size
- emigration
- the movement of individuals out of a popuation
- carrying capacity
- the numbe rof individuals teh environment cna support over a long period of time
- birth rate
- the number of births occuring during a time period
- inbreeding
- mating with relatives
- population density
- measure how drowded a population is
- death rate
- number of deaths during a time period
- exponentail growth
- the larger a populatiosn gets the faster it grows
- dispersion
- teh spatial distribution of individuals within the population
- developed countries
- includes the wworlds modern industrialized countries 20 percent of the world
- age structure
- the distribution fo individuals among different ages in a population
- mortality rate
- death rate
- developing countries
- 80 percent of the world lives in poorer and populaitons gorws much faster
- agricultural revolution
- dramatic chagne in lifestyle, chagnes in every aspect of life
- exponentail model
- population growth describes a population that increases rapidly only after a few generations
- limiting factors
- a factor that restrains the growth of a population
- life expectancy
- how long on average an individual is expected to live
- growth rate
- a population as the amount by which a populations size changes in a given time
- survivorship curves
- show teh likelihood of survival at different ages throughout teh lifetime of an organism