2. Over Population
Population Growth
Theories for Population Growth
Population Structure
Control of Population Growth
References
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3. Population:-
It is define as a group of organisms of the same species
occupying a particular space.
Population density:-
It is defined as a numbers of individuals per unit area per
unit volume of environment.
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4. Over Population
Although people no longer talk about a
catastrophic “population bomb,” world
population continues to grow.
Unfortunately, the most affected
countries are also the ones least able to
support more people.
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5. 5
Reasons for over population:-
Increase In Birth Rate
Decline In Mortality Rate Due To Medical Advance
Increase In Immigration
Illiteracy
6. Increase in Birth rate
Stage 2 in population cycle
High level of natural increase
Large families, 5 children average
High infant mortality
Lack education/ Family planning
50% of population under 18
High Dependency Ratio
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7. If the human population increases rapidly ,it is termed as
population explosion.
If the human population decreases suddenly ,it is termed
as population crash.
India at present is passing through the stage of population
explosion.
The population of India around 350 million in 1947 has
now crossed one billion after 2003. It is estimated to reach
1.45 billion by 2025 and 1.80 billions by 2050 to become
number one over taking china.
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8. Effects of population explosion:
1) Overstress of natural resources:
population explosion causes depletion of natural
resources like water,land,forest etc.
The encroachment of land for human needs like roads,
industrial area,houses,will decrease the fertile land available
for crop production.
2) Increase on demand of food ,Water and services:
Population explosion causes scarcity of food and water.
Shortage in agriculture land and water may also cause
starvation in some parts.
Population explosion creates problems like rush in
transportation facilities education facilities, medical
facilities,etc.
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9. 3) Generation of huge quantity of waste:
Population explosion results in excessive generation of
domestic wastewater, industrial effluents and solid waste.
This creates disposal problems resulting in water, air and land
pollution.
4) Other effects:
Decrease in agricultural land
Reduction in living standard of people
Increase in migration rate
Increase in unemployment
Low per capita income
Energy crisis
High crime rate
Development of slump areas
Deterioration in the quality of environment
Increase in poverty 9
10. Population Growth
Until the Middle Ages, human populations
were held in check by diseases, famines and
wars, and thus grew very slowly.
It took all of human history to reach 1 billion.
150 years to reach 3 billion.
12 years to go from 5 to 6 billion(1999).
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11. => Population Growth rate is the fractional rate at which
the number of individuals in a population increases.
=> Population Growth Rate = ( Population at the end
of period - Population at
the beginning of the
period)
------------------------------
Population at the
beginning of period
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15. Environmental degradation is a result of socio-economical, technological and
institutional activities. Degradation occurs when Earth's natural resources are
depleted. These resources which are affected include:
Water
Air
Soil
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16. The degradation also impacts our:
Wildlife
Plants
Animals
Micro-organisms
Environmental changes are
based on many factors
including:
Urbanization
Population growth
Economic growth
Intensification of agriculture
Increase in energy use
Increase in transportation
Cutting down massive forests impacts our
biosphere.
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17. Unfortunate Impacts of Environmental Degradation
When factories produce harmful chemicals and toxic waste into
bodies of water, humans suffer. Pesticides and fertilizers can
also get into a region's water system and pollute it. Drinking
water is contaminated. Some residing in third-world countries
are highly effected by the degradation of our planet and these
unhealthy practices cause the following:
Illnesses
Death in children
Death in adults
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18. 18
Theories for population growth
There are two very important theories on population growth
1. Malthusian theory
2. Marxian theory
19. The English political economist and demographer the revered
Dr. Thomas Robert Malthus published his treatise ‘Essays on the
Principles of population’ in 1798,when he feared that England was
heading for disaster due to increasing human population.
His theory ,popularly known as ‘Malthusian theory’ is based on
the following assumption:
1) The food is necessary for survival of man and therefore their
existence.
2) Population ,if unchecked, increases at a faster geometric
rate(i.e. 1,2,4,8,16…….) whereas food supply grow at slower
arithmetic rate(i.e. 1,2,4,6,8…….)
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20. In the first preposition Malthus suggests that food is essential for
the survival of the men and the size of population is determined by
the availability of food.
The rapidly increasing population results in less availability of
food per capita.
In the second preposition Malthus assumes that population
increases faster that nature can provide subsistence. This means that
after some time, the human population will out grow the food
production and people will starve and undergo the misery.
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21. Malthus Theory of “Overpopulation”
Malthus Theory of “Overpopulation””
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22. It is the number of people that will produce the highest per
capita economic return given the resources available, and their
full utilization.
Should the population rise or fall from the optimum the
output per capita, and standard of living, will fall.
A country is said to be under populated if it has insufficient
people to make full use of the resources available.
On the other hand a country is overpopulated if there are
too many people and few resources.
There will be diminishing returns.
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24. Education
Living standards and employment
incentives
Government benefits
Publicity
Participation of NGOs
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Control of Population Growth:
25. Population Structure of a Country , can be given
by following features :
1. Birth Rate
2. Mortality
3. Death Rate
4. Sex Ratio
5. Total Fertility Rate(TFR)
6. Age Structure
26. 26
Birth Rate:- Number of child births in a year per
thousand is called as birth rate
Death Rate:- Number of deaths per thousand persons in
a given year.
Sex Ratio:- No. of female per 1000 male.