Population Explosion

Unit 3

Population

Topics

• Development of Habitat patternsEnvironmental factors governing settlement

• Population and Pollution

• Reasons for over population

• Production of Food

• Population growth Demographic projections

Environmental factors governing settlement

• The environment has considerably affected human beingright from his evolution. The environment effects human inmany ways. The environment has affected humanssettlements in many ways. The main factors which affectthe distribution of population and human settlement are

• 1) Relief of a land• 2)Climate• 3) Soils• 4) Mineral Deposits• 5) Water Supply• Environment plays an Important role in deciding population

distribution, density, settlement type and patterns.

POPULATION

• POPULATION may be defined as a group oforganisms of the same species occupying aparticular space.

• OVER POPULATION: Over population is acondition when an organism number exceedsthe carrying capacity of its habitat.

• Over population is not a function of size ordensity it is determined using the ratio ofpopulation to available resources.

Over population

Reasons for Over population

• Increase in birth rate

• Decrease in death rate

• Better medical facilities

• Increase Immigration

• Decrease in Emigration

• Illiteracy

• Increase in birth rate: Birth rate isthe no of child born /1000people/year. With the advent ofbetter medical facility, economicprosperity, social beliefs the birthrate increases which causes increasein population

• Decrease in Death Rate: Death rateis expressed in units of deaths/ 1000persons/year. The development oftechnologies has resulted indecrease in death rate. Good andclean atmosphere, sufficientnutrients, better medial facility hasprovided longer and healthy life.

• Better Medical facility: New inventionsof medicines, awareness towards betterhealth and control of various diseaseslike TB, Small pox, cancer, has resultedin increase of population

• Increase Immigration: The countrieslike usa where the development hadbrought good environment for citizensto stay, earn , and enjoy had resulted inincrease in immigration

• Decrease Emigration: In case ofDeveloping Countries the basicrequirement of citizens like peace,development opportunities are satisfiedhence migration is avoided this maycause over population

• Illiteracy: Due to some social beliefs, lack of knowledge towards family planning, desire for male child are some of the factors which causes increase in population

POPULATION EXPLOSION

• Effects of Population explosionOver use of natural resources

Increase in Food Demand

Increase in waste generation

Other effects like• Unemployment

• Poverty

• Increase in crime rate

• Energy crisis

• Over crowding of cities

POPULATION GROWTH

• Population growth is the change in population overtimeand can be quantified as the change in number ofindividuals in a population per unit time of measurement

• According to population clock every second on an average4-5 children's are born, and 2 persons die, thus resultingincrease is of 2.5 persons every second. That means everyhour there is a growth of 9000 persons and in one daypopulation increase is of the order of 2,14,000

• Current Population of India in 2010 - 1,150,000,000• (1.15 billion)

Population Forecasting

• To Design various infrastructures facilities likewater supply scheme, sewage disposal unit,the basic record of current population andfuture population is must

• Therefore an estimate of future population isnecessary for designing this facilities.

Various Population Forecasting

• Arithmetic Increase method

• Geometric Increase method

• Incremental Increase method

• Decrease rate of growth method

• Graphical extension method

• Graphical Comparison Method

Arithmetic Increase method

• This method is based on the assumption thatpopulation increase at a constant rate

• Thus future population is given as• Pn= Po + nX• Where,• Pn= Future population• Po= Population at present• n= No of decades between now and future• X= average of population increase• This method of population forecasting is used for large

cities which have reached their saturation population

Geometric increase method

• In this method per decade percentage increase orgrowth rate is assumed to be constant and the increaseis compounded over the existing population everydecade.

• Where,

• Pn= Future Population

• Po= Initial Population

• r= rate of growth

• N= no of decades

Incremental Increase Method

• In this method per decade growth rate is notassumed to be constant as in the arithmetic orgeometric increase method but it is progressivelyincreased or decreased depending on past data

• P n= Po + n X +• P n= Future Population

• P o= Initial Population

• X= Average increase in population

• Y= Average of Incremental Increase

• n= no of decades

Decrease rate of Growth Method

• Since the growth rate of Increase in populationgoes on reducing as the cities reach theirsaturation, a method which makes use ofdecrease in the percentage increase, is many atimes used. In this method, average decrease inthe percentage increase is found out and is thensubtracted from the latest percentage increasefor each successive decades. This method ishowever applicable only in cases, where thegrowth rate shows a downward trend.

Simple Graphical Method

• In this method a graph is plotted from theavailable data between time and population.The curve is then extended smoothly up tothe desired year. This method however givesvery approx results

Comparative Graphical Method

• In this method, Cities having Condition andcharacteristics similar to cities whose futurepopulation is to be predicted are first of allselected. It is then assumed that the cityunder consideration will develop, as theselected city has developed in past. Thismethod has logical background and if staticsof similar cities are available vary precisereadings can be obtained.

Control of Population growth

• Education: Literacy plays amajor role in checkingpopulation growth. Improvingthe literacy rate particularly inwoman, can help in populationcontrol

• Incentives: Certain Incentives inthe form of governmentbenefits, scholarships, tochildren, subsidies, exemptionsfrom tax, promotion In jobs,should be offered

• Government Benefits: The governmentbenefits should be allowed only for thosehaving smaller families

• Publicity: The Importance of birth controlmethods for family planning, the significanceof small families and related informationshould be published through various media,schools, books, and other sources.

Food Production

• Nutritious food is the basic needof human beings at every stageof life

• Sources of Food• 1) Agriculture crop: Like wheat,

rice, maize, pulses, vegetablesetc

• 2) Meat and Milk: The meat ofdomestic animals like sheep,goat, hens are used as importantfood resource. The otherimportant food resource, likemilk produced by goat, cow,buffalo etc

• 3) Sea Food: Fish and sea foodcontributes 70 mMT of highquality protein to world’s diet.

Worlds food problem

• Food is one of the basic requirement ofhuman beings it is the most importantmaterial that our body needs. During last 50years food production has increased by 50 %by at the same time the population growthhas out stripped food production. The FAO

estimated that about 840 million peopleremain chronically hungry, nearly 820 million ofthem in the developing countries

Food problems

• Undernourishment• Malnutrition• Every year 40 million people die of

undernourishment and malnutrition.• Undernourishment: It is lack of sufficient

calories in available food, so that one haslittle or no ability to move or work.People who receive less than 90 % oftheir minimum dietary intake on a longterm basis are consideredundernourished.

• Unnourished children can suffer fromstunted growth and mental retardation.

• This can be prevented by better diet,clean water, and simple medicines.

Malnutrition

• Malnutrition is the lack of specificcomponents of food such as protein,vitamins, or essential elements indiet. It is nutritional imbalance dueto lack of specific dietarycomponent. It may occur In both richand poor .Major problems due tomalnutrition

• Marasmus: Lack of protein andcalories

• Anemia: Lack of Iron• Goiter: Due to Iodine deficiency

Population Theories

• There are three important theories ofpopulation, which are of relevance to thepresent trends of population growth. Thetheories are

• Malthusian Theory of maximum population

• The optimum population theory

• The Demographic Transition theory

Demographic Projections

• This Method is used to represent the processof shift from high birth rates and death ratesto low birth rates and death rates as a part ofthe economical development of a countryfrom a pre-industrial to an industrializedeconomy. It is based on an interpretationbegun in 1929 by American demographerWarren Thomson who observed changes inbirth and death rates in industrialized societyover the past 200 years.

• This method represents that there is arelationship between the population change andindustrial growth with time.

• Stage 1 In pre-industrial society , death rates andbirth rates were both high and fluctuated rapidlyaccordingly to natural events, such as droughts,and diseases, to produce a relatively constant andyoung population

• Stage 2 In developing countries the death ratedrops rapidly due to improvement in food supplyand sanitation, which increases life span andreduces diseases, basic health care units and thecountries in this stage experiences great increasein population

• Stage 3: In this stage birth rate falls due toincrease in status and education of women,increase in parental investments. Populationgrowth begins to level off.

• Stage 4 : There are both low birth rates andlow death rates. Birth rate has dropped due tochange and life style and due to medicaladvances and death rate has dropped too. Asa result total population is high and stable.

• Stage 5 : This stage represents developedcountries where population are nowreproducing well below their replacementlevel. And the population growth may tend tobe zero or negative.

Malthusian Theory of maximum population

• English economist and demographer Dr. RobertMalthus gave this theory, according to this theory

• In his first Proposition Population if unchecked,increases at a faster geometric rate (i.e.1,2,4,8,16…) whereas the food supply grow at anarithmetic rate (i.e. 1,2,4,6,8…) . The necessaryeffect of these two different rate of increase willbe striking as after sometime the population willoutgrow the food supply and people will starveand undergo misery.

• In the second preposition Malthus suggeststhat the food is essential for the survival of theman and that the size of population isdetermined by availability of the food. Greateris the production of food larger the size ofpopulation which can be sustained, this resultLess production per capita. This will ultimatelylead to a situation where the number ofpeople will out weight the food productionand the population will plunge into starvation& misery.

• In the third proposition, Malthus concludesthat the tendency of the population toindefinite increase may be controlled by twotypes of checks viz.

• Preventive checks: reduce birth rate

• Positive checks: Increase death rate

• Preventive checks:

• The preventive checks are moral restrainedadopted by the people voluntarily. Such checksincludes marrying late or not at all. It reducesthe birth rate.

• The positive checks are more savage and arenatural. If people do not act on their own, thenature acts in the form of famines, wars,outbreak of diseases. They increase in deathrate.

Population grows in quick geometric progression

(2,4,8,16,32)

Food supply grows in slow arithmetic progression

(2,4,6,8,10)

Imbalance between population and food supply

Corrective measure of imbalance

Positive checksPreventive

checks

Malthusian Theory of population

The Optimum theory of Population

• This is the modern theory of population,propagated by modern economist such asSidewide, Cannon, Dalton, and Robbins

• Optimum means the best or the ideal. Optimumpopulation means the ideal population or theideal number of population the nation shouldhave relative to the natural resources, stock ofcapital investment and state of technology. Inother words, optimum population is that size ofpopulation at which the per capita output is thehighest.

• A country is said to be overpopulated if the populationis less than the optimum and over populated if it ismore than the optimum. Initially population is smallrelative to availability of resources hence due tospecialization and efficient use of resources per-capitaoutput/ income increases to a maximum. This size ofpopulation is the optimum population.

• Beyond this point, if population increases, the countrywill become over populated and per capita output willstart decreasing. Overpopulation leads to low livingstandards, frustration and unemployment

• Both under and overpopulation have short comings . Itis the optimum population which is best suited for acountry. The optimum population is not static numberas it keep on changing with discovery of newrersources and technological developments.

• The theory is further explained graphically, by plotting size of population on X- Axis and per capita output on y-axis

P

R

Q

A

Per Capita/Income

Population Size

Population Dynamics

• Population Dynamics is the study of Change inpopulation.

• The basic Equation of population Dynamics

• The rate of change in the size of population(N), in the course of time, is the function ofpopulation size (N) itself. i.e. the rate ofchange of N is the function of N

• Where,

• = Rate of change of N with time ‘t’

• r= Instanteneous rate of increase

• N= The size of Population

The Exponential Growth

• The basic equation of population Dynamics, relates the Increase with the population size itself, but doesn’t establish a relation between population at two different times, i.e. who to calculate Nt, population after time ‘t’ in years

• Therefore Integrating eq

•

• Leads to Nt=No.ert

• Thanks