CHAPTER 8
HUMAN POPULLATION
Changes in Population Size:
Population: All the organisms of one species living in a defined area
at the same time.
Lag Phase: The period of time in population growth when an
organism is adapting to its new environment and the growth is
slow.
Log/Exponential Phase: When the growth rate of a population
increases overtime as all requirements are in superabundance.
Stationary Phase: when the growth rate of a population has slowed
down to zero as the carrying capacity is reached.
Carrying Capacity: the maximum size of a population that an
environment can support in terms of food, water and other
resources.
History of Human Population:
About 10000 years ago, there were about 5 million people living as
hunter-gatherers. Significant points in the growth of the human
population since then are:
About 6000 years ago, humans started growing crops and
rearing animals, which provided more food and allowed the
population to begin to grow;
By the time the modern system of counting years started, the
population was about 250 million;
It then took another 1800 years to reach 1 billion;
After this, the growth become very rapid;
By 1930, it was 2 billion;
By 1975, it was 4 billion;
By 2016, it was over 7 billion, a rise of 3 billion in just 37 years.
UN Predictions for The Human Population in 2100 Based on
Evidence:
Birth Rate: The number of live births per thousand of population
per year.
Death Rate: The number of deaths per thousand of population per
year.
Natural Increase: The difference between birth rate and death rate.
Factors Effecting Birth Rate:
In countries with a high death rate for the very young (high
infant mortality), birth rates are also high.
In farming economies of many LEDCs, more people are needed
for manual labour ؞families tend to be larger.
In MEDCs, it is expensive to have children and pensions are
provided by the state. As pensions are provided, they do not need
children to take care of them in their old age.
Many social and political factors result in low use of birth control
in LEDCs, whereas in MEDCs birth control is widely used, so
both birth and death rates are lower.
Migration:
The movement of people into (immigration) or out of (emigration) a
region, country or an area.
Most common worldwide movement is from rural to urban areas
in LEDCs.
Sometimes urban to rural migrations also occur, mostly in
MEDCs.
Population Growth:
(Birth rate + immigration) – (death rate + emigration).
Push & Pull Factors:
PUSH FACTORS: factors that encourage people to move away from
an area.
PULL FACTORS: factors that encourage people to move into an
area.
Push from Rural to Urban Pull From Rural to Urban
Good supplies of food whatever
Drought/famine;
the weather;
Poverty; Well-paid jobs;
Poor links with outside world; Good roads;
Hospitals, schools, water,
Poor services;
electricity;
Work on the land only, Factory, shops, office work for a
subsistence; wage.
Desertification;
Sea-level rise; No comparable pull factors
Seasonal weather events.
Human Population Distribution and Density:
Population Density: Population per area (figures providing an
average value).
Population Distribution: how the population is spread over an
area.
Example: very few or no people live in deserts and mountains,
whereas populations are very high in coastal areas due to
availability of fresh water.
Population Structure:
Population/Age Pyramid: A diagram that shows the
proportion of the population that is male and female in different
age groups (usually 5-year interval).
A population pyramid is a graph that shows the distribution of ages
across a population divided down the center between male and
female members of the population. The graphic starts from
youngest at the bottom to oldest at the top.
Expanding (young) Populations: A typical pyramid for LEDCs with
high proportion of young people due to high birth rate.
Definition of. Young population. The youth population is defined
as those people aged less than15
Stationary Populations:
A population is considered stationary if the growth rate is zero
and the age structure is constant.
Population that is almost stationary, with a rectangular shape,
except at the top when old people die.
Contracting (old) Populations (Japan 2016):
Population is declining because of low birth rates, and its pyramid
is top-heavy because of low death rates.
Dependent: those people in the population who are not
economically active (working) i.e. the young (<16) and old (65+) and
thus rely on those who are working for their needs.
Independent: those people in the population who are economically
active (working) i.e. the middle-aged (between 17 and 65).
Taxes from the independent population is used for:
Education for the youngsters and provision of school places for
the children yet to reach school age.
Creating care-home places and hospitals for the ageing
population.
Managing Human Population Size:
Family Planning: Methods used by couples to decide the
number of children to have and when, which is mostly
encouraged by governments
Contraception: used to prevent pregnancy.
Improved Health and Education: Makes people more aware of
methods to limit family size.
Educated women may plan a career as well as having children,
the former frequently limiting how many children are born.
Education can also lead to a tendency for later marriages and
thus later child bearing.
High infant mortality causes couples to have more children.
When it is reduced by better healthcare and sanitation, the trend
is reversed.
National Population Policies:
Pronatalist policy: a national or regional policy that aims to
encourage couples to have children.
In countries like France, couples were encouraged to have
more than 2 children.
Parents are paid the equivalent of the minimum wage for a
year after they have a third child.
They enjoy subsidised train fares, pay less tax the more
children they have, and subsidised day care.
Anti-natalist Policy: a national or regional policy that aims to
discourage couples to have children.
In LEDCs, population increases too fast, and these policies
can form in weak measures such as the provision of family
planning, contraceptives and education, to laws
encouraging couples to have only one child.
Some countries have no population policies at all and
usually have high birth rates.
