XI - Human Population:Growth, Demography, & Carrying Capacity Flashcards
Population chance is calculated as
the difference between individuals entering and leaving a population
Birth rate
reported as the number of births per thousand people
Death rate
reported as the number of deaths per thousand people
Zero population growth
occurs when factors that increase and decrease population size balance
Rule of 70
number of years it takes for an amount growing at x % per year to double is roughly equal to 70/x.
Developed countries tend to have
lower birth rates & death rates than developing countries
World’s most populous nations
China India USA Indonesia Pakistan Brazil Nigeria Bangladesh Russia Mexico
Population size by region
Asia 4.6 B Africa 1.3 B Europe 0.75 B Latin America 0.65 B North America 0.37 B Oceania 43 M
Average total fertility nowadays
2.5 children per woman
How has the total fertility in the United States behaved?
Major increase during “baby boom”
Now hovering below replacement level at 1.8 births per woman
What are significant factors that decrease human fertility levels?
increase in average level of education & affluence;
decrease in importance of child labor;
increased urbanization;
increased cost of raising & educating children;
increased educational & employment opportunities for women;
decreased infant mortality;
higher average age of marriage;
greater availability of private & public pensions;
greater availability of reliable birth control;
greater availability of legal abortions;
change in religious beliefs, traditions, & cultural norms away from encouraging large families.
Birth control method
abstinence sterilization hormonal implant IUD Vaginal pouch Condom Spermicide Cervical cap
Infant death rates are lower in
developed countries than developing countries.
The rapid growth in the world’s population has not resulted from
an increase in birth rates, but rather a major decrease in death rates.
What primarily has caused the exponential growth in human?
Increasing difference between birth & death rates
In developed countries decreases in death rates are being accompanied by
decreases in birth rates over time.
Rate of natural increase is equivalent to
crude birth rate minus crude death rate
In developing countries decreases in death rates have not been accompanied by a
s large of decreases in birth rates over time, leading to major population increase.
Age structure
refers to the proportion of the population in each age class
prereproductive
0–14 years
reproductive
15–44 years
postreproductive
45 & up
What does a population age structure show?
Age structure
Proportions of males vs females
Rapidly growing populations
pyramid–shaped age structures, with large numbers of prereproductive individuals
Slower growing populations
More even age distribution
Rapid growth examples
Kenya
Nigeria
Saudi Arabia
Slow growth examples
US
Australia
Canada
Population with zero population growth
nearly equal proportions of prereproductive & reproductive individuals
Populations with negative growth
greater proportion of reproductive than prereproductive individuals.
Population with zero population growth examples
Denmark
Austria
Italy
Populations with negative growth examples
Germany
Bulgaria
Hungary
Developing countries are expected to continue to have
a pyramid shape through the year 2025, although the age structure will become somewhat more evenly distributed.
Populations of developed countries are expected to have
an increasingly even age distribution through the year 2025.
Population age structure of the United States continues to
show a bulge as the baby boom generation ages. This has been compared to watching a boa constrictor swallow a pig.
The Limits to Growth (1972)
indicated that if current economic, resource use, & population trends continue then we can expect economic & ecological collapse
What basic assumptions of industrial societies did The Limits to Growth challenge?
There are no limits to industrial & population growth.
What does this computer model project might happen if the world’s population & economy continue to grow exponentially at 1990 levels?
It will eventually collapses.
What does computer model project will happen if fertility is stabilized to 2 children per couple?
we can avoid overshoot & collapse to make a fairly smooth transition to a sustainable future.
4 stages of demographic transition
Preindustrial
Transitional
Industrial
Post Industrial
What happens in the Preindustrial Stage
Both birth & death rates are relatively high & approximately equal, such that the population does not increase, & the population size is small
What happens in the Transitional Stage?
Death rate decreases markedly because of industrialization, increased food production, & improved health care; birth rates remain relatively high, such the population grows rapidly.
What happens the Industrial Stage?
Birth rate drops & eventually approaches a balance with death rate, leading to a slowing of population growth.
What happens in the Postindustrial Stage?
approximately balance, zero population growth is attained, & the population stabilizes at a size much higher than the preindustrial size; if birth rate declines below death rate negative population growth may even be attained.
as fertility decreases,
immigration has become a major source of population increase in the U.S
Working immigrants
Boost the economy in the long run
Population control in India
1952 India began national family planning program
What happened with the planning program?
as fertility decreases, immigration has become a major source of population increase in the U.S.;
Why do Indian parents still have many kids?
To take care of them as they get older
Population control in China
1970 - initiated efforts to strictly control population - One Child policy
How can governments reduce population growth
improve access to family planning & reproductive health care;
improve heath care for infants, children, & pregnant women;
encourage development of national population policies;
improve equality between men & women;
increase access to education, especially for girls;
increase the involvement of men in child rearing & family planning;
reduce poverty;
reduce & eliminate unsustainable patterns of production & consumption.
