Population refers to the total number of individuals of a species present in a particular area at a given time. A species can have multiple populations living in various regions.

The scientific study of human population is known as demography. It deals with three phenomena:

(1) Changes in population size, whether growth or decline

(2) The composition of the population

(3) The distribution of the population in space.

Demography also focuses on five demographic processes, including fertility, mortality, marriage, migration, and social mobility. These processes are constantly at work within a population, determining its size, composition, and distribution.

When the population increases rapidly over a relatively short period, it is called a population explosion. The world population was around 2 billion (2000 million) in 1900, and it reached about 6 billion by 2000. A similar trend was observed in India, where the population was approximately 350 million at the time of independence, but it reached close to a billion by 2000 and crossed the 1 billion mark in May 2000.

This means that every sixth person in the world is an Indian. The rapid decline in death rate, maternal mortality rate (MMR), and infant mortality rate (IMR) and an increase in the number of people in the reproductive age group are probable reasons for this. Through our Reproductive and Child Health Care (RCH) programs, we could bring down the population growth rate.

According to the 2001 census report, the population growth rate was still around 1.7 percent, i.e., 17/1000/year, a rate at which our population could double in 33 years. Such an alarming growth rate could lead to an absolute scarcity of food, shelter, and clothing. Therefore, the government was forced to take serious measures to check this population growth rate.

The present growth rate of the human population is approximately 2.5.

Demographic ProcessesDefinition
FertilityRefers to the number of children born to women of reproductive age.
MortalityRefers to the number of deaths in a population.
MarriageRefers to the formation and dissolution of marriages or other types of partnerships.
MigrationRefers to the movement of people from one geographic location to another.
Social mobilityRefers to the movement of individuals or groups from one social class to another.
Fig 1. Demographic Processes
YearWorld Population (in billions)
Fig 2. World Population Growth
YearIndia Population (in millions)
Fig 3. India Population Growth
YearPopulation Growth Rate
Fig 4. Population Growth Rate

Note: The data presented above may be subject to change and may vary based on the source.

Population Growth: Understanding the Four Basic Processes and India’s Census 2011

Population growth is a critical issue that has significant implications for the survival of humans and other species on our planet. Understanding the four basic processes of population growth is essential to comprehend the dynamics of the population. In addition, regular census taking is necessary to track changes in population size, density, and other demographic characteristics. In this presentation, we will discuss the four basic processes of population growth, two types of population growth, and India’s Census 2011.

The Four Basic Processes of Population Growth

  1. Natality: Refers to the birth rate that contributes to an increase in the population.
  2. Mortality: Refers to the death rate that contributes to a decrease in the population.
  3. Immigration: Refers to the number of individuals that have come into the habitat, contributing to an increase in population.
  4. Emigration: Refers to the number of individuals of the population who left the habitat, contributing to a decrease in population.

Two Types of Population Growth

  1. Exponential Growth: Shows J-shaped growth curve.
  2. Logistic Growth: Shows S-shaped or Sigmoid Growth Curve. This type of population growth is called Verhulst-Pearl Logistic Growth, as explained by the following equation: dN/dt = r N (K- N/K) where N = Population density at a time t; r = Intrinsic rate of natural increase and; K = Carrying capacity.

India’s Census 2011

India’s Census 2011 was the 15th national census of India, conducted by the Office of the Registrar General and Census Commissioner of India under the Ministry of Home Affairs. The census was conducted in two phases: the first phase, called the House Listing and Housing Census, was conducted from April to September 2010, and the second phase, called the Population Enumeration, was conducted from February 9 to 28, 2011.

Some key findings of the Census 2011 are:

  1. Population: India’s population was recorded at 1.21 billion, an increase of 17.7% from the previous census in 2001.
  2. Literacy: The overall literacy rate was 74.04%, with male literacy at 82.14% and female literacy at 65.46%.
  3. Sex Ratio: The sex ratio (number of females per 1000 males) in India was 940, an improvement from the 2001 figure of 933.
  4. Urbanization: The proportion of urban population increased to 31.16% from 27.81% in 2001.
  5. Religion: Hindus formed the majority (79.8%) of the population, followed by Muslims (14.2%), Christians (2.3%), Sikhs (1.7%), Buddhists (0.7%), Jains (0.4%) and others (0.9%).
  6. Languages: There are 121 languages which are spoken by 10,000 or more people in India, with Hindi being the most widely spoken language (41% of the population).
  7. Literacy rate was highest in Kerala (93.91%) and lowest in Bihar (63.82%).
  8. The highest sex ratio was found in Kerala (1084) and the lowest in Haryana (877).
  9. Uttar Pradesh had the highest population (199 million) among all Indian states, while Lakshadweep had the lowest population (64,429).

The Census 2011 provided valuable data on the population and socio-economic conditions of India, which is used by policymakers and researchers to formulate policies and programs for the development of the country.

Reasons for Population Growth

There are several reasons for population growth, some of which are:

  1. Improved healthcare: One of the primary reasons for population growth is the improvement in healthcare facilities and medical technology. Advancements in healthcare have reduced infant mortality rates and increased life expectancy, leading to an increase in the overall population.
  2. Lowering of death rates: Improved sanitation, access to clean drinking water, and better nutrition have contributed to a decline in mortality rates, leading to an increase in population.
  3. Increase in fertility rates: In some countries, particularly those with low-income levels, cultural or social factors may lead to high fertility rates, which result in a higher population growth rate.
  4. Immigration: Immigration, particularly in developed countries, can contribute to population growth. The influx of people from other countries can contribute to the overall growth of the population.
  5. Lack of family planning: In many developing countries, there may be a lack of access to family planning and birth control methods, leading to unintended pregnancies and higher population growth rates.
  6. Economic factors: In some countries, a larger population can lead to increased economic growth and development. This can lead to policies that encourage population growth, such as pro-natalist policies.

Consequences of Overpopulation

Overpopulation can have a range of consequences on both the environment and human society. Some of the consequences of overpopulation are:

  1. Strain on resources: With more people, there is increased demand for resources such as food, water, and energy. This can lead to depletion of natural resources, environmental degradation, and strain on infrastructure.
  2. Increased pollution: As population density increases, so does pollution. This can lead to air and water pollution, increased carbon emissions, and negative impacts on the environment and public health.
  3. Spread of diseases: Overcrowding and poor sanitation can lead to the spread of communicable diseases such as tuberculosis and cholera. Increased population density can also lead to the spread of diseases such as COVID-19.
  4. Conflict over resources: As resources become scarce, competition for them can lead to conflict and social unrest.
  5. Pressure on infrastructure: As the population grows, there is an increased demand for housing, transportation, and other infrastructure. This can lead to overcrowding, congestion, and strain on existing infrastructure.
  6. Economic strain: Overpopulation can lead to increased unemployment, as there are more people competing for jobs. This can also lead to lower wages and economic inequality.
  7. Loss of biodiversity: As human populations grow, natural habitats are destroyed to make way for housing, agriculture, and industry. This can lead to loss of biodiversity and negative impacts on ecosystems.

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