Population: Birth & death Rate, Sex Ratio | Additional Study Material for NEET PDF Download

Population

DEMOGRAPHY

Scientific study of Human population is called "Demography". (Demo = people, graphos = to write)

Population – Population is defined as the total number of individuals of a species present in a particular area at a given time(A species have many population living in different regions).

CENSUS :

Official counting of individuals in first 4 month of I^st year of each decade is called census.

Population of World : 

2000 – 6.1 billion

3,36,960 – Child born per day

1,46,960 – Person dies per day,

so there is increase in population 1,90,000 per day.

Max. Population : China 1997 – 1244 million

Min. Population : Switzerland – 8.8 lack

Population of India : 

Ist counting – 1872

Ist Census in India – 1891

Census – 2001

Population – 1.02 Billion (53%  – males,  47%  – females)

–India completes 17% of total world population.

It is on 2^nd place in world population.

Every 6^th person in world is an Indian.

In land area, India covers only 2.4% of world land area.

India lies on 7^th place in land area.

World population day : 11 July. (Every year from 1987) On this day 5^th billion child of world population was born.

1. Population Density (P.D.) : No. of persons living in per square km. area

 World – 33/km² 

Maximum (Most thick population) – Bangladesh (Previously Japan)

Minimum – Greenland  – 15 /km² (Previously Australia)

India – 324 person / km²(2001) 

2. Birth Rate :

Crude Birth Rate (C.B.R.) – Birth rate at per thousand population is called as crude birth rate.

C.B.R. – India – 24 birth/1000/yr.

Maximum – State : U.P. – 35 (1991) Rajasthan– 31 (2001)

Minimum – State : Kerala –18

3. Death Rate :

Crude Death Rate (C.D.R.) – Death rate at per thousand population is called as crude death rate.

India C.D.R. – 8 death/1000/yr.

4. Population Growth : Human population growth rate is measured as the annual average growth rate which can be calculated as follows :

Annual Growth Rate : CBR – CDR = 24 – 8 = 16 person/1000/yr.

If percent annual growth rate of a country is 2% then population will double itself after 33 yrs (doubling time) 

Growth Rate : 

Developed – 0.8%

Developing – 2.5%

Sweden – 0%

Kenya – 5.5%

India Growth Rate :

(1) 1965-70 – 2.1%

(2) Now – 1.6% (1.7% according to 2001 census) 1921 is known as big divide year of Indian population. Before 1921 in (1911–1920)

CBR = 49.9 & CDR – 47.9 so % AGR = 0.2% ≈  0%

But after 1921, population increases at very fast rate.

Population Growth : 

Positive growth – Natality + Immigration

Negative growth – Mortality + Emigration

Zero growth – (Natality + Immigration) = (Mortality + Emigration)

5. Infant Mortality Rate (I.M.R.) : 

Infant – Children upto one year after birth

Neonates – upto 28 days after birth (or one month)

Perinates – Child less then one week.

 (Dead born or still born child are not counted)

 India : 

– 57 (Now)

– 67 (2001)

– 72 (1991)

Maximum – M.P. – 89 (1991) Rajasthan – 85 (2001)

Minimum – Kerala – 15

World :

Maximum – Bangladesh – 100

Minimum – Japan – 4 (Developed countries < 10)

U.S.A. – 8

I.M.R. reflects the socio-economic development of country 

It is a most sensitive index of health & level of living of people.

6. Maternal Mortality Rate (MMR) :

India – 3 Female/1000/yr.

Developed country – Japan – 0.1 female/1000/year

7. Sex Ratio : 

Number of Females / 1000 males

India – 933 : 1000 (2001)

Maximum – State : Kerala (1058 / 1000), U. T. : Pondichery (1001 / 1000)

Minimum – State : Haryana (861 / 1000), U. T. : Daman & Diu (709 / 1000)

World – sex ratio – 1:1

8. Literacy : 

A person can read and write with understanding in any language is called literate.

India –

65.38 (2001)

52.2 (1991)

Maximum – Kerla (90.92%)

Minimum – Bihar (47.53%)

Growth rate depends on following factors – 

1. Birth rate or Biotic potential or Fertility or Natality : Biotic potential is maximum natality or birth rate that can be achieved under ideal condition of environment (GR may be Negative but B.R. never be Negative) It is the ability of reproductively active individuals to produce babies, fertility is the determinant of the current growth of population.

Fertility rate varies from region to region. The more developed countries have lower fertility rate (close to replacement level) than the developing.

Fertility is largely controlled by economics. High fertility in developing world is partially explained by large number of hand needed to perform work. Technology task, as the technology improves parents realise that having more children lead to lower standards of living. This realisation leads to a lower fertility rate.

2. Mortality or Death Rate : In most countries, the death rate has dropped almost continuously since the industrial revolution, mainly due to improved health services. A decrease in death rate would result in increase population growth rate.

3. Migration : Migration is the movement of Individuals into (immigration) or out of (emigration) a place or country.
Immigration minus the emigration is called Net immigration, which is added to the population growth by birth (Natality).

PGR = (Natality + Immigration) – (Mortality + Emmigration)

4. Age and Sex Structures : The age structure of a given population refers to the proportion of individuals of different age. This is important aspect because many functional aspect of individuals are related to age. (Like Reproduction) Age structure of a population can be depicted in the form of a pyramid diagram.

• Developed countries have a steeper pyramid which represent a nearly stable population.
• Developing countries (like India) represented by a much less stepper pyramid.
• Infants (below one year of age) and older people have higher mortality rate than individuals of other ages.
• The population of reproductive active males and females in a population influence the birth rate and population growth.

Diagram is particularly important in understanding future growth.

Population has 3 age groups.

(i) Pre-Reproductive individuals – < 15 yr

(ii) Reproductive individuals – 15 – 44 yr

(iii) Post-Reproductive individuals – > 45 yr

• A higher number of pre-reproductive individuals, moderate number of reproductive individuals and fewer post reproductive individuals will form young population it shows rapid growth.
• Fewer number of pre-reproductive individuals as compared to reproductive ones will make population aged. It shows negative growth.
• An equal number of pre -reproductive and post reproductive individuals will constitute a mature population or stable population.