19 Anthropology of Population Dynamics

Urvashi Gupta and Meenal Dhall

Contents:

1. Introduction

2. Birth Rate and Death Rate

3. Major components of Population Dynamics

3.1 Fertility

3.2 Mortality

3.3 Migration

4. Tracing World Population Growth through History

5. Future Projections

6. Population Processes and Global Changes

Summary

Learning outcomes

1. To know the interrelation between Anthropology and Demography

2. To understand different components of population dynamics

3. To get insights about the historical aspect of the world population growth

4. Future projections and global changes related to population processes would become clearer

1. Introduction

Anthropology is a generalizing and comparative discipline with a concern for understanding human diversity on global scale. Anthropologists engage in empirical research with established theories, methods and analytical techniques. They conduct field-based research as well as laboratory analysis and archival investigations. A hallmark of Anthropology is its holistic perspective–understanding humankind in terms of the dynamic interrelationships of all aspects of human existence. Different aspects of culture and society exhibit patterned interrelationships such as polity, economy, social configurations, religion and ideology. When anthropologists collaborate with demographers, or use demographic tools and research techniques particularly for understanding the dynamics of a population they are termed to be as ‘Demographic Anthropologists’.

Demography as the science of human population deals with population structure and processes, along with other associated parameters of population study. For this it draws research from a number of disciplines, including economics, sociology, geography, public health, and genetics. In addition to the environmental impacts of population growth, it also considers the causes of population growth or decline. With a vast expansion, the discipline traces the influence of these dynamics on the economic and social well-being, its impact over poverty; impact on age structure, sex imbalance, population redistribution (or migration) on social, economic, environmental development.

Demography is about analyzing the growth or decline of human populations and changes in the structures of various related facets. To demographers, population could be any group of persons who can be delimited on the basis of some observable characteristic. The most common way is to define the population on the basis of residence within a given geographical area. Demographers refer to a population as all those inhabiting within any boundary. Such boundaries are usually divisions between administrative regions and need not have any effect on the past or present. However, practitioners from other social science disciplines are not so interested in establishing any objective definition of a population. Far more important for them is to establish the ways in which human groups define themselves and those around them, usually involving the interaction of complex social, cultural and/or ethnic features.

2. Birth Rate and Death Rate

Birth and death rates are the most important determinants of population growth. In some countries, net migration is also important in this regard. Until the mid-19th century birth rates were only slightly higher than death rates. Resultantly, the human population grew very slowly. The industrial era changed many factors that affected birth and death rates. In doing so, it led to a dramatic expansion of the world’s population. The mechanization of agriculture enabled societies to produce more food from available inputs that altered the population growth rates sharply. As food supplies expanded, average levels of diet intake rose, and vulnerability to chronic and contagious diseases declined over succeeding generations. Improvements in medical care and public health care services, that took place more in urban than in rural areas also helped people to live longer. So death rates fell.

After several decades of lower mortality, people understood that they did not have to have so many children to achieve their desired family size. So birth rates began to fall gradually. In addition, the desired family size also tended to decrease. Women were then were less inclined to devote resources to childrearing, and gave preference to paid job and works. This happened as they found several opportunities to enter the working sector. The jobs they had were not conducive to have children beside them as they worked. The costs of raising children also increased, as slightly wealthier families living in urban areas faced higher expenses for a larger array of physical and social necessities.

The process of phased reduction in death and birth rates is called demographic transition. It alters population growth rates in several stages. Because death rates fall before birth rates, population growth initially speeds up (it is a phase sometimes referred to as the mortality transition), adding a large cohort of young people to society. This group in turn would have children, although probably fewer per family than their parents did. Because this group of childbearing-age people is large, population would continue to grow in absolute numbers even though on a per-capita basis birth rates will decline. Demographers call this phenomenon fertility transition.

Continued population growth after a fall in birth rates is called population momentum. It accounts for a significant portion of world population growth. Today the global fertility rate has declined from about 5 children born per woman in 1950 to a little over 2.5 in 2006.

Many developed countries have passed through the demographic transition, and most developing countries are at some point in the same process today. As a result, a bulge/baby-boom (generation, distinctly larger than those preceding or following it), is moving through the age structure of the population in nearly all countries. Such large cohorts create both opportunities and challenges for society. Expanded work forces can help nations increase their economic output, raising living standards for everyone. They also can strain available resources and services, which in turn may cause shortages and economic disturbance. Shifts in population age structure have important effects on resource demand.

3. Major components of Population Dynamics

Fertility, mortality and migration are mechanisms for numerical change. All three processes are likely to affect and to be affected by global change. These components of all population structures tend to change over time. They all act as the major vehicles of population dynamics and provide a thread to the continuity of any population.

The processes by which the frequency of genes changes within a population are mutation, natural selection, migration and genetic drift. Natural selection and genetic drift are caused by differences in fertility and mortality rates. By linking knowledge about the processes of molecular and population change to the available human DNA information, that is still accumulating world-wide, a new comprehension of the evolutionary dynamics of populations; admixtures and subdivisions; origins and the rate of growth is now becoming accessible.

3.1 Fertility

Fertility or total fertility rate is the number of births that can be expected to occur to a typical woman in a given society. This is accounted during her childbearing years. Fertility is a function of a woman’s fecundity, along with the social, cultural, economic, and health factors that influence their reproductive choices. Fecundity is defined as a woman’s physiological ability to conceive and bear children. The most important non-physical factors influencing a country’s total fertility rate include:

relationship status (the fraction of women who are married or in a relationship that exposes them to the possibility of becoming pregnant)
use of contraception
the fraction of women who are infecund
the prevalent abortion rates

Fertility levels are higher in developing countries than in developed nations because most women in developed countries work outside of the homes, tend to marry later, use contraception and undergo abortions to delay or prevent childbearing. Fertility rates, in nearly all countries have been falling since the 1950s. Most of the exceptions are seen in the Central and Western African regions.

Fertility patterns can vary widely within countries. Racial and ethnic minorities may have higher fertility rates than the majority. Families with low income or lower levels of education tend to have more children than those who are affluent or well-educated. Women who work outside the home generally have fewer children than those who stay home, and rural families have more children than city dwellers. The number of births per 1,000 people worldwide averaged to 21 in 2006, with extremes ranging from a low of 8 or 9 (mainly in northern and western Europe and some former Soviet republics) to 50 or more in a few west African nations.

In the book ‘Essay on the Principle of Population’, T.R. Malthus compared his contemporary European society with ‘more uncivilized ones’ in regard to what he termed as ‘positive checks’ on fertility.

3.2 Mortality

A population’s age structure is an important factor that influences its death rate. Death rates are highest among infants, young children and the elderly. In a way, societies with many elderly people are likely to have more deaths per 1,000 people than those where most citizens are young adults. Developed countries with good medical services have more people in older age brackets than developing countries. Therefore, the developed societies can have higher death rates even though these are healthier places to live overall.

To assess longevity in a society, demographers calculate life expectancy. Life expectancy is the age that a newborn would, on average, live to, assuming she/he was subjected to a particular set of age-specific mortality rates, usually those prevailing in a particular year. The probability that a child will die at a given age drops through childhood and adolescence after she/he passes through the vulnerable early years. Life expectancy is moving up around the world, but still a substantial gap remains between developing and developed countries. In 2006, life expectancies at birth ranged from the mid-30s in some African countries to the 70s or 80s in the United States, Australia, Japan, and some European countries.

Life expectancy serves as a measure of the general health of a population.

It depends on the satisfaction of many basic human needs such as adequate nutrition, clean water and sanitation, as well as access to medical services like vaccinations. Addressing these requirements reduces the incidence of many preventable diseases. For example, nutritional deficiencies cause common disorders like scurvy and pellagra, while dirty water and poor sanitation spread infectious diseases such as cholera and typhoid.
New threats to health are continuously emerging. They often spread across international borders through trade and human or animal migration. Recent examples where the diseases were severe enough to affect life expectancy in large areas include the HIV/AIDS pandemic, multi-drug-resistant malaria and tuberculosis.
Researchers are also gaining new insight into existing threats, such as indoor air pollution from combustion of primitive biomass fuels like crop waste and dung. Exposure to these pollutants is a major factor contributing to lower life expectancy in developing countries. Environmental investments, such as providing cleaner energy sources and upgrading sewage treatment systems, can significantly improve public health.
Another step that increases life expectancy is creating a public health infrastructure that can identify and respond quickly to disease outbreaks, famines, and other threats. For example, when severe acute respiratory syndrome (SARS) emerged as a disease, the U.S. Centers for Disease Control and Prevention (CDC) then began an emergency response program that required health departments to report suspected cases to CDC for assessment, developed tests for identification of the SARS virus, and kept health care providers and the public informed about the status of the epidemic. Their SARS cases were then reported to the World Health Organization by the United States and many other countries. These types of close surveillance and preventive steps to control infections can help preventing diseases from spreading extensively.

3.3 Migration

Migration is the geographic shift by populations within nations and across borders. Migration is less predictable over long periods than fertility or mortality, as it can happen in sudden waves. For example, when refugees flee a war, or move slowly over many years. Immigration often changes the organization of the host nations’ or regions’ ethnic groups and also strains their social services. On the positive side, it can provide the needed labor, both skilled and unskilled. For resourceful countries, however, immigration may drain away valuable talent, as educated and motivated people are most likely to migrate in search of opportunities. In the short term (5 to 15 years), migration (both within and across national boundaries) is likely to be highly dynamic and well correlated with global change.

4. Tracing World Population Growth through History

In the early decades of the Industrial Revolution, life expectancies were low, not only in developing nations but also in the developed countries. Thousands of people died from infectious diseases mainly typhoid and cholera. These diseases spread rapidly because the conditions were crowded and filthy that was common then. Also people were weakened by poor nutrition. But from about 1850 through 1950, series of health and safety advancements and provisions radically improved the living conditions in industrialized nations. Major milestones included:

improved urban sanitation and waste removal
improved quality of water supply and expanding access to it
formation of public health boards for the detection of illnesses and quarantine the sick
understanding the causes and means of transmission of infectious diseases
development of vaccines and antibiotics
adopting workplace safety laws
banning child labor
promoting nutrition through fortified milk, breads, and cereals with vitamins and minerals supplements.

By the mid-20th century, most industrialized nations had undergone through the similar demographic transition. As health technologies were transferred in developing nations, many of these countries entered the mortality transition and their population expanded. The world’s population growth rate rose in the late 1960s at just over 2 percent per year in developed nations while 2.5 percent in developing countries. Many researchers forecasted that the population growth was out of control, then. However, the world population growth rates that peaked in the late 1960s have dropped sharply in the past four decades. The world’s total population is still rising because of population momentum stemming from large increases that occurred in developing countries in the 1950s and early 1960s. But fertility rates are falling as many developing countries have passed through the demographic transition. It occurred mainly because of lower infant mortality rates; expanding rights and education, labor market opportunities for women; and increased access to family planning services.

5. Future projections

World population growth in the 21st century will not be the as in the previous decades in several important ways:

First, humans are living longer and having fewer children, so there would be more number of older people (age 60 and above) than very young people (age zero to four). Second, majorly all population growth will take place in urban areas as compared to the rural regions. Third, fertility rates will continue to decline.
All of these trends will affect nations’ economic development.
Senior citizens can be active and productive members of society, but at the same time they have many special needs in areas ranging from medical care to housing and transportation.
Social services will might be strained by the growing elderly populations, especially in countries that do not have well- developed social safety nets to guarantee adequate incomes for older citizens.
Increasing ratios of older to younger people may create budget imbalances because fewer workers are paying funds into the system to support growing numbers of retirees.
As the societies age, demand for younger workers will also increase, dragging more people into the labor force and attracting immigrants in search of job opportunities.
Declining fertility rates that are witnessed when more women work outside the home, will increase the labor supply and may further accelerate the demographic transition.

6. Population Processes and Global Changes

There is a need for more fundamental appreciation of the linkages between population processes and global environmental changes taking place. Population growth, composition, and distribution have important interconnections with land use patterns, land cover, and global climate change. They also affect the needs for other kinds of natural resources because, for any given combination of technology, energy use patterns, and social organization, population can have important multiplying effects in association with global change. The need for policy responses to global change varies with the size, composition, and distribution of populations. Demand for policy responses is also affected by the populations that would realize the impact of global change. Consequently, integrated assessment and policy analysis need to take into consideration the likely size and spread of affected human populations.

In considering population processes, it is of utmost importance not to assume that causality flows in just one direction. Environmental factors also influence population processes. For example, environmental quality, including climate, is one of the prime factors influencing migration destination choices. Declining environmental quality and decreasing productivity of land may force people to shift their habitat. Drastic environmental or climatic alterations may also lead to increased mortality. Thus, it is important to carry out empirical research on both the effects of population dynamics on global change and of global change on population dynamics. In addition, it is important to understand that association between population and global change can operate through or be mediated by other driving forces, such as economic or policy changes. For example, the effect of a resettlement program on an area may depend on the policies of the resettlement agency.

Summary

Human population dynamics is a field that identifies the factors related to changes in population such as fertility, mortality, life expectancy and migration. Predicting population changes is important because these demographic trends effect economic, social, and environmental systems. Birth and death rates are the most important determinants of population growth. All three processes are likely to affect and to be affected by global change. These components of all population structures tend to change over time. They all act as the major vehicles of population dynamics and provide a thread to the continuity of any population. Population growth, composition, and distribution have important interrelationships with land use, land cover and global climate change. It is important to go for empirical research on both the effects of population dynamics on global change and of global change on population dynamics. In addition, it is significant to recognize that relationships between population and global change can operate through or be mediated by other driving forces, such as economic or policy changes.

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References

Population dynamics Thematic Think Piece UNDESA, UNFPA. 2012. UN System Task Team on the Post-2015 UN Development Agenda.
Macbeth, H., & Collinson, P. (Eds.). (2002). Human Population Dynamics: Cross-Disciplinary Perspectives (Biosocial Society Symposium Series). Cambridge: Cambridge University Press.
https://www.learner.org/courses/envsci/unit/pdfs/unit5.pdf
ttp://www.aaanet.org/about/whatisanthropology.cfm
ttp://anthro.ufl.edu/files/about_anthropology.pdf https://www.nap.edu/read/9175/chapter/7#32

Suggested Readings

Duncan, O.D. 1959. Human ecology and population studies.
Kertzer, D.I. and Fricke, T.E. 1997. Anthropological demography: Toward a new synthesis. University of Chicago Press.
Raj, H. 1981. Fundamentals of demography: Population studies with special reference to India.

Terms and concepts associated with Population studies

Population Dynamics includes changing in size, density dispersion and age distribution, in response to environmental conditions.
Population Size is the number of individuals in a population at a given time.
Population Density is the number of individuals of a population in a certain space at a given time.
Population Dispersion is the spatial pattern in which the members of a population are found in their habitat.
Age Structure – the proportion of individuals in each age group in a population.

Pre-reproductive

reproductive

post-reproductive

A population with a large percentage of its individuals in the pre-reproductive and reproductive categories has a high potential for growth.
Four variables that govern population size :

births

deaths

immigration

emigration

Population change = [ births + immigrations ] – [ deaths + emigration ]

Population change = [ births – deaths ] + [ immigrations – emigration ]