This document discusses human population and its relationship to the environment. It covers topics like population ecology, growth, density and carrying capacity. It also discusses factors governing human settlement like land, food, water and energy resources. It describes population pollution due to overpopulation exceeding environmental carrying capacity. Reasons for overpopulation include high birth rates, low death rates, migration and illiteracy. Effects of overpopulation include increased demand for resources and generation of waste. The document also discusses population growth rates, theories of Malthus and Marx, and methods of population control and forecasting.

1. Chapter 4
HUMAN POPULATION
AND
ENVIRONMENT
YASH PATEL

2. Population Ecology

3. INTRODUCTION
• Population : The word population has been
derived from the Latin word “populatio” which
means people.
• The group of individual species which occupy a
definite geographic area is defined as
population.
• Population Growth : The change in population
per unit area at particular time is called
population Growth.

4. Population density :Population density is
defined as the number of individual or people
per unit area in per unit volume of
Environment.
Carrying Capacity : Maximum population size
indefinitely supported by available resources .

5. Human Settlement
• The human settlement can be defined as
communities who live in city, village or town
with all social, material ,organizational, spiritual
and cultural elements which exist and sustain
for long time.
• The human settlement needs natural resources,
physical elements as well as services to sustain.
• These components comprises of fresh clean air,
water , food, shelter and services include like
education, medical facilities.

6. Environmental factors governing
human settlement
• LAND : As population increased , people
started taking over more and more land for
human settlements. Land was used to develop
infrastructures like roadways , public complexes
and industries.
• FOOD : With the increase in population , there
was a demand for more and more food and so
more land was started to be used for
agricultural activities.

7. Development of advanced technologies in the
field Of agriculture caused use of fertilizers and
pesticides for increasing productivity which
deteriorated the quality of environment and
health of human beings.
• Water Resources: High population and
settlement of human beings in different places
caused the problem of water scarcity due to
unequal distribution of water resources and
unplanned use of these resources for
industrialization and urbanization.

8. • ENERGY RESOURCES : Conventional energy
resources started depleting due to high
demand of increased population for energy.
• FOREST RESOURCES : Due to increased
population , use of more land area for human
settlement and industrialization also
increased.

9. Population Pollution
• Population pollution is the pollution caused due
to overpopulation.
• Overpopulation is the condition when the
population (number of organism) exceeds the
maximum carrying capacity of the
environment.

10. Population Pollution
• The maximum carrying capacity of environment
is the capacity to support human beings with the
availability of food , water , shelter, as well as
protecting human beings against the extremities
in environment.
• Over population is not a function of size or
density of the population.
• Determined by calculating ratio of population to
available sustainable resources.

12. Reasons for Overpopulation
High Birth Rate :
• The crude birth rate is the number of child’s birth per
1000 people per year.
• If the birth rate is high , it implies more number of
people will be for human settlement and will therefore
cause overpopulation.
• Birth rates are affected by a number of factors :
– Social beliefs
– Religious beliefs
– Mortality rate
– Literacy
– Economic prosperity
– Abortion rate

13. Low Death Rate:
• Decline in mortality rate
• The crude death rate is the number of deaths
per 1000 people per year.
• Low death rate is basically due to technological
advancement in the field of medical science
which reduced the mortality rate.
• Other reason for this may be: Average age ,
Nutritional levels, Standard of diet and housing,
Access to clean water, Hygiene level.

14. Migration :
• People from towns and villages generally
migrate to cities in search of jobs and better
living standards which overpopulates the cities.
• Similarly, people from developing countries try
to migrate to developed countries making them
overpopulated.

15. ILLITERACY :
• People of lower and poor classes generally have
larger families due to poor education facilities.
• In India, particularly in villages , due to religious
beliefs or due to eagerness to have a male child
people tend to have big families.

16. Effects of Population Explosion
• Population Explosion: When the population
increases suddenly, it is termed as population
explosion.
• Population Crash : When the population of
human beings decreases , it is called population
crash.
• It is different from Overpopulation, since this
condition arises when economic development
fails to maintain pace with the population growth.

17. Effects of Population Explosion
1. High Demand Of Basic Needs : Population
explosion causes scarcity of food and increase
in the prices of food items.
• It also leads to the formation of slums in big
cities.
• Shortage in agricultural land and water may also
cause starvation in some parts.
• It creates problems like rush in transportation,
education and medical Facilities.

18. 2. Reduction In Natural Resources : Population
Explosion causes depletion in natural resources
due to more consumption of these resources
by the people.
It leads to high consumption of fossil fuels ,
minerals and forest resources.
More forest will be cut down to provide wood
for housing and fuel.
More water is required for drinking, irrigation
and industrial purpose.

19. 3. Generation Of Huge Quantity Of Waste:
• Population explosion results in generation of
wastewater , industrial effluents and solid
waste which poses the stresses over the
facilities for disposal of wastewater.
• Causes ecological imbalance

20. 4. OTHER EFFECTS :
(a) Increase in migration rate and reduction in
living standard of people.
(b) Reduction in agriculture land.
(c) Increase in unemployment
(d) Deterioration in the quality of environment
due to pollution in soil , air , water and air.
(e) High crime rate
(f) Energy crisis
(g) Increases number of slums

21. Population Growth Rate
• The population growth can be expressed by
Population Growth Rate.
• Population Growth Rate is the fractional rate
at which the number of individuals in a
population increases.

22. Exponential Growth Rate
• In these , the rate of change of population is
directly proportional to population at that
time.
• If after time ‘t’ population is Nt and r is the
rate of population growth , then
dNt/dt= rNt
Nt=Noert
• The above mentioned equation is used for
calculating Exponential Growth Rate.

23. • Doubling Time : The time required for a
population to double itself is called the
doubling time.
• In these, when Nt=2No , t=td, then the
equation becomes
td=0.693/r

24. Logistic Growth Rate
• Rate of increase of population never
remains constant but varies with time.
• It is also called as S-shaped or Sigmoidal
growth curve.
• This curve is density-dependent.
dN/dt=rN{1-N/K}
where,
N=Population size
K=Carrying capacity
r=Logistic growth Rate

25. • The factor (1-N/K) is called environmental
resistance and it becomes negative when
population exceeds carrying capacity and thus
factor (1-N/K) is responsible for achieving
logistic growth from exponential growth.
• Logistic Growth is divided into three phases:

26. • Phase-I : In this phase, population size is
much less than the carrying capacity and
rate of growth is proportional to population
size
• Phase-II : In this phase, increase in
population is rapid compared to phase-I
and growth is steady . (dN/dt=Constant).
• Phase-III : Here , population growth
decreases as population approaches to
carrying capacity i.e. dN/dt=0.

27. PREDICTING POPULATION GROWTH,
Two modes of population growth.

28. • The Exponential curve also known as J-curve.
It occurs when there is no limit no population
size.
• The logistic curve also known as S-curve. It
shows the effect of limiting factor ( in these
case the carrying capacity of environment.

30. Population Growth Theories
• There are two important theories of
population , which are related to the present
trends of population growth.
• MALTHUSIAN THEORY :
• He born in 1766 -1834.
• Wrote “ An essay in the first principle of
population” first in published in 1798.

31. • Passion between sexes is necessary and will
remain unchanged
• Food is necessary for the existence of
humankind

32. • Malthusian theory states that, human
population increased with exponential rate
while the ability to grow food increased
arithmetically.
• Population grows at a geometric rate i.e. 1, 2,
4, 8, 16, 32, etc.
• Food production increases at an arithmetic
rate i.e. 1, 2, 3, 4, etc.

33. The Core principles of Malthus
• Food is necessary for human existence.
• In these , Malthus suggests that the food is
essential for the survival of man and that the
size of population is determined by the
availability of the food.
• Human population tends to grow faster than
the power in the earth to produce
subsistence(food).

34. • A point will come when population overcome
the food source resulting in crisis
• Limiting the population in line with carrying
capacity requires “ strong checks”. Preventive
Checks and Positive Checks.
• Positive check: disease outbreak
• Preventive check: control of birth rate
• In above mentioned point , Malthus
concludes that the tendency of the population
to indefinite increase may be controlled by the
two types of checks.

35. • Preventive / Negative Checks : “This suggest to
reduced or decreased birth rate” .
preventive checks - postponement of marriage
(lowering of fertility rate), increased cost of
food etc.
positive checks – These checks lead to an
increase in the death rate. Famine(shortage of
food), war, disease, would increase the death
rate.

36. Limitations of Malthus Theory
(A) Malthus did not consider migration of people.
(B) Malthus failed to recognize the potential of human
population to increase food supply.
(C) He also did not consider man’s ability to use science
and technology, advancement in the field of
agriculture to increase food supply, family planning
methods.
(D) He has confused the instinctive desire for sexual
relationship with the desire to have children

37. Malthus (cont.)
Population grows
geometrically….
Population exceeds carrying
capacity…
Population is kept in “check”–
preventative and/or positive
checks

38. Marxian Theory
• Full Name: Karl Heinrich Marx
• Birth: May 5th, 1818
• Death: March 14th, 1883.
• Also called theory of surplus population
• Karl Marx believed that depletion of natural
resources, existence of poverty and pollution
as well other social ills present in the society
are indicated by the population growth.

39. • Therefore, population increase is an indicator
rather than a cause of these problem.
• According to him , there can be no universal
law of population.
• He believed that man’s tendency to pressing
the means of subsistence(the means by which
one maintains life) is due to the evils of
capitalism which would disappear with the
emergence of communism.

40. • As a result unemployment spreads , wages
decline and poverty increase.
• He came to the conclusion that main cause of
surplus of population was nothing but the
wrong politics of the capitalists.
• Marx stated that poverty and unemployment
is not only due to increased population but
due to capitalist system which failed to
provide the job.

41. Control of population growth
1. Education
2. Living standard and employment
3. Government benefits and
incentives
4. Publicity
41

42. Control of population growth
• 1.Education
• Improvement of literacy rate in villages and
lower and middle class of people, particularly
in women can control the population growth.
• 2.Living standard and employment
Employment will improve the living standard
of people so there will be improvement in
education and awareness of family planning
which could control the population growth.
42

43. 3.Government benefits and incentives
• Implementation of government
policies to give special incentives to
people having only two children and
benefits to such children in education
later on ,may play an important role in
control of population growth.
43

44. 4.Publicity
• Publicity by giving advertisements and
incentives, stating importance ,need and
significance of birth control and family
planning may also control growth.
44

45. Population Forecasting Method
• The data regarding present and past
population of any city is always available from
the records of municipal corporations but to
design a new water supply scheme or waste
water treatment plant, the current and future
population must be forecasted.
• Following are some methods of population
forecasting:

46. Methods of population forecasting
• Arithmetical increase method
• Geometrical increase methods
• Incremental increase method
• Graphical extension methods
• Logistic curve methods.
Other:
• Zoning Method
• Decrease rate of growth method
• Ratio and correlation method

47. • Arithmetical Increase Method :Principle of
this method is that the rate of change of
population with time is constant as show
below.
• dp/dt = constant
• For past three to four decades , data for future
population is calculated by the following
formula:

48. Pn= P + n I
Pn=population forecasted
N=Decades
P=Present population
I=Average Increment of a decade

49. Geometrical increase methods
• Principle of this method is that the percentage
growth rate of population with time is
constant.
• For the past three or four decades , data for
future population is calculated by the formula
given below.
Pn = Po{ 1+r/100}n

50. • Po= Initial population
• Pn= Population forecasted for n decades.
• r= % growth rate of population
NOTE= This method is used only for those cities
having high population growth.

51. DEMOGRAPHIC PROJECTION
• Demographic projections are used to represent the
increase in population, shift has been from high birth
rates and high death rates to low birth rates and
death rates.
• Demographic transition (DT) refers to the transition
from high birth and death rates to low birth and death
rates as a country develops from a pre-industrial to an
industrialized economic system.When the birth rates
and death rates are equal then zero population
growth rates are observed which is called as
“Demographic Transition”

53. • There are four stages of demographic stages:
• Phase-I: Due to lack of awareness, poor medical
facilities, low education levels and natural disasters,
high birth rates and high death rates are there.
• Phase-II : In developing countries , due to
advancement in technologies and improvement in
medical facilities and Education system, death rates
dropped rapidly compared to corresponding birth
rates. This caused high increase in population in
countries.

54. • Phase-III: In this, due to urbanization and
industrialization, reduction in natural resources,
women’s education and family planning scheme,
high reduction in birth rates was observed which
tried to level off the population growth.
• Phase-IV : In this phase , both birth rates and death
rates are low. High living standards and more jobs by
women lead to reduction in fluctuating birth rates
and death rates are also low because of high
technologies and excellent medical facilities.

55. • Phase V: In developed countries like UK
where population are now reducing well
below their replacement level and population
growth may tend to negative or zero.
• This theory cannot predict correct future
population as it does not consider factors like
population migration.

57. Population Structure
• Infant Mortality Rate: Measure of mortality rate which
is deaths of infants per 1000 births, in a given year.
• Natural increase of population: difference between
crude birth rate and crude death rate
• Sex ratio: number of females per 1000 males
• Total fertility rate is average number of children that
would be born to a women during her life time
• Age structure: Pre-productive 0-14
Reproductive 15-44
Post productive >45

58. Urbanization
• Growth in the proportion of a population
living in urban area is called urbanization.
• In developing and less developed countries,
urbanization results due to demographic and
economic pressure.
• People migrate to bigger urban centers to
seek jobs and other social services.

59. Environmental and Socio-economic
problems due to Urbanization
• Demand for dwelling place: as the population
increases more and more land is required.
• Overcrowding: as people migrate to urban
areas for employment opportunity, education
and medical facility leads to the overcrowding
of urban areas.
• Increase crime: increase unemployment and
poverty leads to increase in growth rate of
crime.

60. • Exploitation of ground and surface resources:
demand for different resources like water,
electricity, fossil fuel etc. will increase with
population increase.
• Increase of air pollution
• Generation of solid and liquid wastes
• Pressure on habitants of wild and domesticated
animals

61. Thank You