Studied by 2 peopleconsequences of exponential growth
increased demand for food/water/land
demand for food → raising livestock → deforestation
loss of habitat endangers species
loss of forest degrades air/water quality
congested areas promote spread of disease
more pollutants released
more waste generated
crude birth rate (CBR)
number of live births per 1,000 people in a population per year
CBR = births / population * 1,000
crude death rate (CDR)
number of live deaths per 1,000 people in a population per year
CDR = deaths / population * 1,000
natural increase rate (NIR)
rate of population growth, not accounting for immigration of emigration; percentage
NIR = (CBR - CDR) / 10
doubling time (DT)
time (years) for a population to double
DT = 70 / NIR
replacement level fertility
the number of children a couple must have to replace them (2.1)
total fertility rate (TFR)
estimate of the average number of children a woman will have per year, if she passes through her childbearing years conforming to the age-specific fertility rates of a given year
TFR > replacement level
population growth
TFR < replacement level
zero/negative growth
contributing factors to total fertility rate (TFR)
urbanization
increasing opportunities for women
reduce infant mortality rate
delay women’s age when she first gives birth
pensions for retirees
availability of abortions & birth control
avoiding dogmatic religion & tradition statutes
factors that reduce death rates:
urbanization (more resources/medicine)
better healthcare
increased access to food
sanitation and potable water
first stage of the demographic transition model (DTM)
ex: a few remote groups
CBR: high
CDR: high
increase: stable/slow
reasons for changing birth rate:
children work
high infant mortality rate
religion/societal pressures
no family planning resources
reasons for changing death rate:
disease/famine
little to no medical care
second stage of the demographic transition model (DTM)
ex: Egypt, Kenya, India
CBR: high
CDR: falling rapidly
increase: rapid
reasons for changing birth rate:
children work
high infant mortality rate
religion/societal pressures
no family planning resources
reasons for changing death rate:
medical care
good water/sanitation
more children live
third stage of the demographic transition model (DTM)
ex: Brazil
CBR: falling
CDR: falls slowly
increase: slower
reasons for changing birth rate:
more medicine/food
reasons for changing death rate:
medical care
good water/sanitation
more children live
fourth stage of the demographic transition model (DTM)
ex: US, Japan, UK
CBR: low
CDR: low
increase: stable/slow
reasons for changing birth rate:
urbanization
healthcare
family planning
reasons for changing death rate:
healthcare
reliable food source
age-gender pyramids
shows the proportion of the population, by sex, at each for different age levels
How do predictions made about population growth by age structure diagrams influence economic decisions?
pensions
social security
job competition
more people = more consumers = greater need for jobs
large population provides a taxable base for supporting retirees
more people = greater environmental footprint
factors contributing to population growth
universal access to family planning
better healthcare for pregnant women/children
equality- more opportunities for women
increased access to education
increased involvement in child-rearing for men
eradicate poverty
sustainable use of natural resources
cultural attitudes about family size
government policies
abiotic factors
light
temperature
nutrient level
biotic growth factors
high reproductive rates
generalized niche
adequate food supply
suitable to habitat
ability to compete for resources
ability to hide/defend from predators
ability to migrate/live in other habitats
ability to adapt to environmental change
biotic decrease factors
low reproductive rate
specialized niche
inadequate food supply
unsuitable/destroyed habitat
too many competitors
can’t run/hide from predators
can’t resist disease/parasites
can’t migrate
can’t adapt to environmental change
Note
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