Unit 3 Flashcards
Density dependent factors
a factor that influences the individuals probability of survival and reproduction that depends on the size of the population
Limiting resource
a factor that can slow down or stop a population from growing because it is not an infinite resource
Carrying capacity (k)
the maximum number a population can carry
Density independent factors
a factor that has the same impact on a population no matter the size
Example of a density independent factor
Natural disasters
Population growth models
can be used to describe the growth of a population on a graph. Can be
Population distribution
how individuals are spread in an area
Population size (N)
the total number of individuals in an area at a given time
Random distribution
random distribution. Ex. trees
Uniform distribution
Even distribution everywhere. Ex plantation
Clumped distribution
high distribution in some areas. Ex in areas where resources are concentrated, social groups, or predators and flocking birds. Is the most common dispersion
Intrinsic growth rate (r)
the maximum number of individuals a population can have when environment and resources are optimal
Exponential growth model
when a population grows at their intrinsic rate
Age structure diagrams
show the distribution of individuals in each age group through population pyramids
Sloped triangle pyramid
shows a stable growth where there are a ton of young people but very little old people
Top heavy
when there are more old people than young people. Means that the population will shrink
Column
when there are an even amount of old and young people. Means that the population will stay the same
Population momentum
when a country keeps growing despite growth reduction measures
Theory of Demographic Transition
a theory that describes the changes in population, mortality, and fertility based on industrialization
Pre-industrial stage
slow population growth because CBR and CDR are the same. There is high mortality
Transitional stage
rapid population growth because the nation industrializes and there is low mortality because of better living conditions. There is a cultural lag
Industrial stage
stable population growth because CBR falls when people have access to contraceptives and become richer. Cultural lag catches up with them
Post industrial stage
Declining/stabilizing/0 population growth
Bottom heavy
a ton of younger people than older people and shows rapid population growth
What stage are most developed countries in?
Post industrial stage
Total fertility rate
the average number of children a woman will have in her child bearing years
Replacement rate average
2.1 children
