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Human Population refers to the sum number of human inhabitants living in a particular area (maybe a small place, a state, a country or even the world). Although other animals do not possess any specific ability to alter nature, humans and their actions have the ability to change the environment. So, the attributes of the human population become extremely important to study.
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Keyterms: Population, Human, species, social customs, economic prosperity, technological advancement, health, education, crime patterns, language, culture
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Human Population
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In Biology, the term ‘population’ refers to a group of individuals of the same species residing in a particular area. Thus, a human population refers to the total number of humans inhabiting a particular area. The population is relatively young on this planet. The evidence of the earliest humans is about 200,000-year-old. The current number is somewhere near to 7.8 billion and it’s estimated to reach 9 billion by 2050. This sharp increase has a significant effect not only on the other animals but also on the planet earth. The human population is spread over 6 continents where they have permanent residence and Antarctica without any permanent settlement.
As with every biological population, the human population is also subjected to various factors like food resources, diseases and other environmental factors that control the size and the characteristics of the human population. What is unique about the human population is that it is influenced by various other factors such as social customs, economic prosperity, technological advancement, health, education, crime patterns, language, culture etc.
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Studying human population: Demography and Demographic data
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The science of studying the human population is called Demography. It is a multidisciplinary approach that takes inputs from various other fields encompassing sociology, economics, statistics, biology, mathematics, anthropology and history. Demography deals with various aspects of population size, structure and growth. The understanding of the demography enables us to project the future population growth and its pattern.
Demographic data is collected by the respective governments of the country. It includes vital statistics registries – all births and deaths and other changes in status like marriage, divorces and migration. Census is the most valuable tool to collect demographic data. It is conducted by the government every 10 years where information like age, sex, education, employment status etc.are recorded.
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Demographic Measurements
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The vital registries and the census data which is collected are used for measuring the population characteristics, distribution and growth patterns. Some of the population measurements are described below-
- Birth Rate: The number of live births per 1000 people in 1 year is called the Birth rate
The crude birth rate (CBR) is equal to the ratio of live births (b) in a year divided by the total midyear population (p), multiplied by 1,000 to arrive at the number of births per 1,000 people.
CBR= b/p x1000
- Mortality Rate: It accounts for the number of deaths per 1000 people in 1 year.
The crude death rate (CDR) is equal to the ratio of deaths (d) in a year divided by the total midyear population (p), multiplied by 1,000 to arrive at the number of deaths per 1,000 people.
CDR= d/p x1000
- Fertility Rate: It denotes the average number of live births per woman by end of her childbearing years.
- Replacement Fertility Rate: It is the fertility rate at which the population exactly replaces itself from one generation to the next.
- Life Expectancy: It is the statistical measure of the average time span an individual is expected to live. It denotes the average length of life in a population.
- Population growth Rate: it is the net number of the individual increased in a population in a given period.
- Carrying capacity: the maximum population size of a biological species that can be sustained in a particular environment is called the carrying capacity of that particular habitat.
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Population Composition
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Age-sex Ratio
It is a crucial and frequently measured population parameter. The Age-Sex ratio denotes the number of individuals of each sex and age group in a population and is represented by a special bar graph called ‘Population Pyramid’. It not only allows us to predict population growth but also helps to associate the growth with economic development in that particular region.
Countries with rapid growth show a pyramidal structure as the birth rate is very high and there is a preponderance of younger individuals who are approaching their reproductive age. This pattern is often followed by the underdeveloped countries where the number of older individuals is considerably low as they do not live in sub-optimal living conditions and have inadequate health infrastructure.
The age-sex structure shows slow growth also shows a pyramidal structure with many fewer young and reproductive age individuals and a greater number of older individuals. In such cases, the growth rate is slower and life expectancy is higher. Developed countries like the U.S shows this type of age-sex structure.
On the other hand, in other developed countries like Italy, Switzerland the pyramid is more conical as the proportion of the middle-aged and the older people is much higher and the net growth rate is almost zero.
In the fourth case, both the natality and the mortality rates are low. Economically developed countries in Africa and Asia tend to show this trend.
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The ethnic and racial composition
Ethnicity refers to the national, cultural, religious, linguistic or other attributes that are perceived as distinct characteristics of a particular group. Such divisions are socially important and the statistics of such ethnic and racial compositions are therefore commonly available. However, with respect to the age-sex ratios, this component is far less objective as a measure.
Geographical distribution
The human population is scattered across space. The population density of a particular place is a significant measure denoting the pattern of growth there. Another important aspect of the geographical distribution of the human population is that there is a division between rural and urban areas. It has become important as rapid urbanization in many countries is quite fascinating. . The developed countries show a huge degree of urbanization while the process of urbanization is in the juvenile stage in the underdeveloped countries.
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Theories of Population Growth
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Malthusian Theory
The malthusian theory tries to establish a relationship between exponential human growth and arithmetic food supply growth. He opined that a balance between the two can be achieved through positive and preventative checks.
The Darwinian Tradition
Although Darwin himself was not involved in the debates about human populations. His theories of ‘natural selection’ have been extensively used in the context of human population growth. The differential fertility amongst the different genetic stocks significantly influences population growth. In this view, as the fertility rate differs amongst the biologically superior and inferior human genetic stocks, the quality of the human race tends to decline.
Theory of Demographic Transition
The biological explanation of population growth is crude as the socioeconomic contributing factors are not included here. The Demographic Transition theory rationalizes the explanation of fertility decline as a consequence of a widespread desire of fewer children. It is a result of technological advancement, industrialization, urbanization, higher literacy rates and declining mortality rates.
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Human Population growth and trends in the World Population
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The human population is experiencing exponential growth even though human reproduction is far below its biotic potential. As a consequence of such growth, there is a reduction of the time it takes to add a particular number of humans to the planet. For instance, if we see the data, in the 1930s it would take 123 years to add 1 billion people to the world but it only took 24 years to add 2 billion people between 1975 and 1999.
As mentioned in this article, humans have the unique ability to modify their surroundings but increasing the carrying capacity indefinitely may be limited. Although technological advancements have predicted slower growth in the upcoming decades, a threat of overpopulation looms.
Things to Remember
- Human Population refers to the sum number of human inhabitants living in a particular area (maybe a small village, a state, a country or even the world)
- The human population is also subjected to various factors like food resources, diseases and other environmental factors that control the size and the characteristics of the human population.
- The science of studying the human population is called Demography. It deals with various aspects of population size, structure and growth.
- Birth Rate is the number of live births per 1000 people in 1 year.
- The mortality rate accounts for the number of deaths per 1000 people in 1 year.
- The fertility Rate denotes the average number of live births per woman by the end of her childbearing years.
- Replacement Fertility Rate is the fertility rate at which the population exactly replaces itself from one generation to the next.
- Life Expectancy is the statistical measure of the average time span an individual is expected to live. It denotes the average length of life in a population.
- The population growth rate is the net number of the individual increased in a population in a given period.
- The Age-Sex ratio denotes the number of individuals of each sex and age group in a population and is represented by a special bar graph called ‘Population Pyramid’.
- The human population is experiencing exponential growth even though human reproduction is far below its biotic potential.
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Sample Questions
Ques: Define population? (2 marks)
Ans: Population refers to the sum number of individuals of the same species, living in a particular area (maybe a small place, a state, a country or even the world).
Ques: What is demography? (2 marks)
Ans: The science of studying the human population is called Demography. It deals with various aspects of human population size, structure and growth. It is a multidisciplinary approach that takes inputs from various other fields encompassing sociology, economics, statistics, biology, mathematics, anthropology and history.
Ques: If an organism has to overcome stressful conditions for a limited period of time. Which strategies can it adopt to do so? (2 marks)
Ans: If an organism has to overcome a stressful condition for a limited period of time, it may adopt any or both of the strategies given below-
- Migration- The organism may migrate to a different place and thereby avoid the stress factor occurring.
- The organism may go hibernation/ spore formation etc. depending on the species to suspend an active life.
Ques: What does a J-shaped curve indicate in population growth? (2 marks)
Ans: If a population is exhibiting a J-shaped growth curve it implies that the population is growing in an exponential manner and the availability of the resources is abundant.
Ques: What is the replacement fertility rate? (2 marks)
Ans: The replacement fertility rate is the fertility rate at which the population exactly replaces itself from one generation to the next.
Ques: What are the factors that affect population growth? (2 marks)
Ans: The factors that affect the growth of a population are birth rate, death rate, emigration and immigration.
Ques: What is carrying capacity? (2 marks)
Ans: In nature, the maximum population size of a biological species that can be sustained in a particular environment is called the carrying capacity of that particular habitat.
Ques: In a population, there were 2000 human beings. 150 new individual babies were born over a period of one year? Calculate the birth rate. (2 marks)
Ans: Birth rate of the population = No. of babies born/ Total no. of individuals
= 150/2000= 0.075
Ques: What is an Age-pyramid? Explain different types of age pyramids exhibited by the human population. (3 marks)
Ans: The Age-pyramid refers to the graphic representation of the no. of individuals in the different age groups of a population at a given time.
- When the age distribution (percent of individuals of a given age or age group) in a population is graphically plotted, it is called the age pyramid.
- The population at any given time is composed of individuals of different ages.
- For the human population, the age pyramids generally show the age distribution of males and females in a combined diagram.
- The shape of the pyramids reflects the growth status of the population whether it is expanding (triangular shaped), stable (bell-shaped) or declining.
- The expanding pyramid shows that no. of individuals of the lower age group is very high who are about to enter their reproductive age. The no. of individuals of old age is very low, probably due to inferior health facilities.
- The stable pyramid shows that there are many young and reproductive age individuals and a greater number of older individuals. Here, the growth rate is slower and life expectancy is higher.
- A declining pyramid shows the proportion of middle-aged and older people is much higher and the net growth rate is almost zero.
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