MALTHUS THEORY OF POPULATION GROWTH: EXPLANATION AND CRITICISMS

MALTHUS THEORY OF POPULATION GROWTH

Thomas Robert Malthus gave his idea about population growth in his famous book    " Essay on the principle of population as it affects the future improvement of society"

published in 1798 and modified some of his conclusion in 1803.

CLASSICAL THEORY:

The Malthusian Theory Explained the relationship between the population growth and food supply.He stated that population increases faster than the food supply.

The Malthusian stated two mathematical concept to explain the trends of population growth.

1.  Arithmetic Progression: The food supply progresses slowly as land is constant.The food supply increases in such ways 1,2,3,4,5,6,7,8,9,10 and so on.

2. Geometric Progression: The population increases in successive time such as 1,2,4,8,16,32,64,128,256 and so on

Therefore, Imbalance condition will be created.As the trends of population growth is faster than the supply of food so that he predicted that population will be double at 25 years.

To control over the growth of population ,Malthus suggested two checks 

1. The positive Checks
2. The preventive Checks

He stated that positive checks operates in form of famine , flood , natural disaster , war which reduced the population, and balanced the food supply.He also stated the preventive checks which depend on man's activity such as late marriage,celibacy and moral restraint etc.

CRITICISMS:

The Malthus theory was widely discussed and criticized during 19th and 20th century.

1. The two mathematical concept i.e arithmetic and geometric progression  were not related in reality because there are some developed countries where population growth is very low that will take 200 years to double
2.  Land is limited but improvement of technologies, there must be increased the food production.
3. He neglected the man power but he didn't think if the population is high then man power will high

However there was many criticism in Malthus theory but still his theory is very much important. as we have seen in many developing countries were standing second stage of demographic transition model in which the birthrate remained same and death rate  declined so that population increased which effected the growth of a country,thus the population should be controlled.

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DEMOGRAPHIC TRANSITION IN INDIA

WHAT IS DEMOGRAPHIC TRANSITION ?

The term demography means the structure of population and The term transition means the transfer from one stages to another stages.so that The demographic transition is the shifting in demography from one stage to other.

Warren Thompson in 1929 observed a tradition of birthrate and death rate which had a grate impact of socio economic condition at a particular place.Following Thompson,there was two more who gave the idea of demographic transition,they were Notestein and Blacker.

Classical stages of Demographic Transition:

1. High birthrate and High death rate = High stationary stage

2. High birth rate and Falling death rate = Early expansion stage

3.Falling birthrate and Low death rate = Late expansion stage

4.Low birthrate and Very low death rate = Low stationary

5.Very low birthrate and low death rate= Decline

DEMOGRAPHIC TRANSITION

 The gap between birthrate and death rates during the transition is called "Transitional Growth".

 Thus, The population moves from high mortality replacement level to low mortality replacement level.

IN WHICH PHRASES INDIA BELONGS TO?

The European counties,Asian and Latin American countries followed the classical theory but the time and pace were different.In case of Indian context,the pattern is followed the classical theory but rate of change is very slow.

The declination of death rate is started to fall in 1920 birthrate was remained same up to 1960. Therefore,the growth of population was very high.

After 1960 the birthrate started to fall but death rate was still declining and continuing the population growth. The Natural increase might be declined in last decades.Finally India is moving through demographic transition from third to forth stages.

TRENDS AND DIFFERENTIALS IN MORTALITY:

The Crude birthrate was very high over 40/1000 population during early 20th century but a sharply fall below 40 in 1920s, it was 30 in 1940s. After 1960s it reached 20 and it was 10 in 1990s. Now in 2011 census is showing the rate of crude death rate is 7.1.

The life expectancy in India was below 20 years in 1911-1921 , Had increased 30 years in 1931-40,40 in 1951-60 and 50 years in 1970,it has been increasing 60 in 1990 now Life expectancy was 68.56 years in 2016.

TRENDS IN FERTILITY

Fertility was always high in past . Crude birthrate was 40/1000 in 1920, After 1960 ,a steadily fall of total fertility rate with 22.1.In 2011 census is showed 2.4 / 1000.now it is 2.2.

POPULATION GROWTH

India's population increased from 238 million in 1901 to 1210 million in 2011 which is more than quadruple.The rate of population growth was same up to 1921 and pick up after 1921.The rate of slowing growth noticed after 2001 with decadal growth 20%. The latest census shows a clear fall ,a decade growth of 17.6%and annual rate of 1.62%.

India is in the process of Demographic transition and is entered now in the phrases of falling fertility and low mortality ,Thereby reducing population growth.

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GLOBAL HYDRO LOGICAL CYCLE AND WATER BALANCE

WHAT IS HYDRO LOGICAL CYCLE?

we know earth has one - third of water.it is found at three form i.e solid form like ice ,liquid form like rivers,oceans and lakes , and gaseous form. The hydro logical process is a very important process in the globe where water is exchanging through atmosphere,biosphere,hydrosphere and lithosphere in cyclic manner.it is referred to as cyclic movement of water through the process of evaporation,transpiration,evapo-transpiration,condensation and finally precipitation within the earth.The water cycle, also known as the hydro logical cycle or the H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth.

Process of Hydro logical Cycle:

The process of hydrological cycle starts while sunrays falls on the water bodies,get evaporate to form water vapor. This water vapor moves upward to the higher altitude.This water vapor forms cloud through the process of condensation.when cloud becomes heavier ,falling on the ground through precipitation in form of rain,hail,snowfall,sheet and so on.

Precipitation while falling on the ground,some portion of water evaporates and returns to atmosphere before reaching earth's surface, some portion of water reaches to the ground and infiltrates into the soil enriching the ground water table as well as maintaining the moisture contain of soil. 

Some portion of water flows over the ground through runoff and falls on the oceans.two type of runoff is occured in the earth surface i.e. surface runoff (  the running of water over the land surface and discharge to the rivers,lakes,ponds and oceans.)  and Sub surface runoff ( infiltrating of water moves towards the rives and water bodies )

Infiltrating of water into the soil gets absorbed by the roots of vegetation which is also returned to the atmosphere through the process of Transpiration.

Some of water returned through evapotranspiration to the atmosphere.

Some of water is left as depression storage.

Further this process is again repeated on the earth surface in cyclic manner.

Components of Hydrological Cycle

Evaporation:- The process in which water gets heated up and forms in water vapor state.

Transpiration:- The absorption of water by the roots of vegetation releases the water which returns to the atmosphere.

Evapotranspiration:-The process in which evaporation and transpiration occurs together.

Condensation:-The process in which water vapor transfers in liquid State.

Precipitation:- Precipitation fall on the ground in form of rain,snow ,hail,mist and so on.

Infiltration:- When water moves into the ground and absorbs by the roots, stems as well as enriches the water table and soil contents.The pervious soil is more infiltrated than impervious soil ,on the other side,The soil like sand is more infiltrated than clay soil.

Runoff:- The running of water which cannot be infiltrated, flowing over the land and discharge into the ocean

Possible ways that Precipitation falls on the ground:

 Precipitation falls on the earth surface in various ways such as 

1. Direct flow : Precipitation falls directly in rivers , oceans and other water bodies is called direct flow

2. Stem flow: Some portion of rainfall is intercepted by the vegetation.some portion is evaporated ,remaining portion reaches the all branches of the trees

3. Through Flow : Some portion of reaches directly on the ground is called through flow.

4.Ground water storage:Some portion infiltrates and enriches the ground water table.

5. Runoff: Some portion of water flow over the land through runoff

IS HYDRO LOGICAL CYCLE CLOSED SYSTEM?

When sunrays fall on the ocean,evaporating from the ocean,transpiration from the vegetation and evapotranspiration is balanced by returning water into atmosphere through precipitation and runoff.,Thus it is called closed system.It is a good example.  water is neither added or lost ,the amount of water is remained same.It just moves from to one to other storage.

WATER BALANCE:

Water balanced is defined as calculating the inputs and outputs amount of water.how they balanced in atmosphere of any period.

The water balance can be shown :

 precipitation (P) = stream flow (Q) + evapotranspiration (E) +/- changes in storage (S) P=Q+E +/- S. The water balance affects how much water is stored in a system.

•  Precipitation = 100 units on ground, 424 units from ocean
• Evaporation= 61 units from land, 385 units from ocean
• Surface outflow = 38 units
• Sub surface outflow = 1 unit
• Atmospheric moisture flow = 39 units 

Thus water is balanced in any water basin in this ways.

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