POPULATION DISTRIBUTION AND CHANGE

CHAPTER 02
POPULATION DISTRIBUTION AND CHANGE

POPULATION DISTRIBUTION

World distribution of population in term of continents and countries, the world’s population is very ill-balanced. More than half of the world’s people live in Asia (excluding the former USSR) which accounts for only one-fifth of the world’s land area, while north, central and south America together, occupy more than a quarter of the land surface, have only one-seventh of population the African continent also accounts for a quarter of land surface but has just over one-tenth of world population. On the other hand, Europe, whose area is only one twenty-fifth of the total, has about one-ninth of the world’s population.

The inhabited area of the world’s land surface is called “ecumen” and uninhabited or sparsely populated areas are referred to as “non-ecumen”.

Definition of the term Population distribution (based on the comparison):

(a) Is the way in which people are spread over the space or an area.

(b)  Is the occurrence or non-occurrence of people in a certain area.

(c) Is either low number of people or high number of people in an area.

Therefore; Population distribution varies from one place to another hence population is unevenly distributed. Sometimes population distribution may be similar with or goes with population density.

Population density (a) Is the number of people and the area they occupy.

                           (b) Refers to the number of people per unit area.

Population density distinguished by high density (densely populated) to low density (sparsely populated).

Factors influencing population distribution (and population density)

Population distribution and density are influenced by the following mainly two factors.

(a)    Physical factors

(b)   Human factors

(c)    Historical factors

(d)   Political factors

(e)    Economical factors

(a) Physical Factors /Natural Factors   

1. Climate.

In this factor, rainfall and temperature are the main elements of climate. Areas with reliable rainfalls do attract high population, but where there is poor rainfall like in desert areas, there is low population. In addition, area with very high (Harsh) temperature do not attract many people, while the areas with low (moderate) temperature, attracts many people.

2. Relief/Topography.

Where the slope is steep, there is low population due to the poor soil and nature of the land, but, where there are gentle, slopes or flat surface, there is high population since the soils are good. Sometimes highland areas do attract people due to the good climatic condition or people being free from floods unlike to the low land areas.

 

3. Vegetation.

The area that is densely vegetated, people are discouraged to live in such areas due to the presence of harsh wild animals and poor transport and communication system unlike to the areas that are sparsely vegetated (there are many people).

4. Soil (edaphic factor).

Infertile soil discourage settlement since does not support agriculture. While good and fertile soil attracts many people, good example is the place of river Nile in Egypt, and Southern parts of Kilimanjaro Mountain.

5. Mineral and Energy Resources.

The areas with minerals and energy resources attract population (for example Geita (in Tanzania) unlike to the place that have no minerals and energy the population tends to be low.

6. Natural hazard/calamities.

Areas faced with Natural Hazards like flood Earth quakes, Tsunami, drought do not influence people to live in such areas, hence low populated, while in the areas with absence of frequent attack of natural catastrophes, normally the areas are populated.

7. Biological factory (Disease and pests)

People like settling in areas which are free of diseases and pests, while the place that are frequently attacked by diseases (e.g. malaria, HIV/AIDS, Tb, Ebola) and pasts (e.g. Locus) people do not prefer to get settled on such areas hence the areas will be low populated.

(b) Human Factors

These factory also known as anthropogenic factors those include the following factors.

1. Political factors.

Area with political stability and peace, tend to attract people and mostly those areas are more populated, while areas or places with political instability like presence of civil wars, tribe wars, ethnic wars, region wars, discourage population increase. In addition, government policies that influence resettlement scheme creation of National parks and forest reserves also influence population to be low on such areas.

2. Social cultural aspects.

Traditional beliefs like superstation influence low population to the area, while in absence of such beliefs, population seemed to be high in an area. Some tribes do not leave the areas because their ancestors for settlement hence high population may be found in such areas used the places.

3. Economic factors.

Present of employment opportunities, banks, markets, industries influence the places to be highly populated unlike to the place that has no such influences hence there will be low population.

4. Transport and communication.

In presence of transport and communication in place may also influence the high population density unlike to the places that have not transport and communication system.

5. Historical factors.

Low population in some place of Africa Influenced by the effects of slave trade and colonization by Europeans also influence the variation of population as well as tribal conflicts and wars influence the variation of population.

POPULATION CHANGE.

Population change refers to the increase and decrease of population in a particular area at a given time. Population change is the result of change in birth, death and migration.

Population change also can be determined as population dynamics. Sometimes population change or growth can be described by the increase of population (is the positive population growth) and the decrease of population (is the negative population growth).

Population change can be:

1.      Change in change size

2.      Change in structure

3.      Change in distribution

4.      Change in composition

Components Of Population Chance           

The following are the components of population change (population dynamics).

(i)                 Fertility or Birth

(ii)               Death or Mortality

(iii)             Migration (Both emigration and immigration)

Note (1) Birth and Death are the natural change while migration is the Artificial Change.

    (2) Population change has input, output and process (see the model provided below)

NATURAL CHANGE ARTIFITIAL CHANGE

TOTAL POPULATION

DEATH

EMIGRATION

BIRTH

IMMIGRATIONNON

PROCESS

OUTPUT

INPUT

 

Birth Rate or Fertility Rate

Fertility rate refers to the occurrence of live birth in a population. Fertility refers to the ability to conceive or to reproduce.

             Fertility rate =    Live Birth      x 1000

                                        Population

Birth rate is measured by crude Birth rate, which is calculated as follows

       

           C. B. R = No of live Birth   x 1000

                          Total population

Called crude birth rate, because it includes all ages and both sexes

Live birth is ability of women to bear a child. Live birth or still birth is called fecundity. Lack of fecundity is called infecundity or sterility. Infecundity is the inability of a woman to bear a child especially for those who cannot give a live birth.

Why High Fertility Rate?    

The following are some of the reasons for the high fertility rate;

(i)                 Improved health measures and medical services.

(ii)               Younger age marriage (early marriage)

(iii)             Cultural factors like; Many children as the source labor (main power), having many children as the source of securing, naming relatives, sex preferences, poor family palming to mention by few.

Mortality or Death Rate

Mortality/death rate refers to the number of deaths within the population.

Infant mortality rate is the number of deaths in a first year of live per 1000 live births.

Child mortality rate is the number of deaths of children aged between l and 5 year per 1000 births.

Adult mortality rate refers to the number of adult dying per 1000 of the total population.

Mortality measured in term of crude death rate (CDR).

Why High Death Rate?   

Reasons for high death Rate are:

(i)                 Poor social services

(ii)               Diseases

(iii)             Wars

(iv)             Accidents

Factors Influencing Population Change.                                                                                    The following are the factors that may influence the increase or decrease of population:

1. Birth rate. High fertility rate may lead to the increase of population. (look for factors cause for high birth rate)
2. Death rate. Mortality rate may cause for the decrease of population. (Refers to the causes of death rate)
3. Migration. Migration refers to the movement of people from one place to another at a given period of time with specific reasons. Migration can be categorized into two; Emigration and Immigration.

Migration may also influence for the population change through both the increase (immigration) and decrease (emigration) of population to a particular area

4.  Cultural Beliefs. Cultural beliefs may lead to the increase of population through; early marriage, sexual preferences, naming relatives etc.

5.  Health services Poor Health services may cause for the increase of death hence population change. While, if there are in proved social service like hospital may lead to the increases of birth lives hence population increase.

Effects Of Population change.

The effects of population change are into;

(i)                 effect on the individual levels

(ii)               effect on the nation levels

Effect of Population Change at Individual Level

Fertility rate results in a large number of children that family has to look after. Very many children may cause poor health of the mother. High impact mortality rate in a family may lead to family problem like witchcraft for blaming relatives or neighbors that they caused for mortality of the impacts.

Migration has the following impact at individual levels.

(1)    Separation of spouses. Due to the one have migrated to other place away with his/her spouse.

(2)    Spread of disease. One person may cause for spread of disease in the fact that a migrant from a particular area may spread certain decease to his/her destination area. Such decease like HIV/AIDS, TB cholera is easily to be spread. 

(3)    Cultural destruction. Due to the people may interact with other traditions, may lead to the alteration of culture of a person.

Effect of Population Change at National Level   

Is very common to the industrialized countries. Decrease of Death rate may lead to the increase population in the country hence over population in the country that may cause for unemployment, high pressure on resources and services.  But in least developing countries, death rate is high that may lead to the effect of low population in the country that may lead to the shortage of man power, underutilization of resources among others.

OPTIMUM POPULATION
By definition, optimum population can be defined as equal relationship between the available resources and the number population in an area.

The size, distribution and structure of the population within a country must be viewed in relation to its natural resources and the techniques of production used by its people. The extent to which resources are used and the way in which they are used determine whether an area is under or over populated.

A country is said to have optimum population when the number of people in balance with the available resources. Optimum condition can only be maintained if the exploitation of new resources or the development of other forms of employment keeps pace with increases in population. If the population becomes too large, the law of diminishing returns begins to operate.

Once the optimum population has been reached, however, a further increase may increase production but at decreasing rate, so that output per capital declines. Under population and over population, therefore must be considered mainly in terms of the stage of development of the country concerned, and the standard by which this is measured.
 

OVER POPULATION

Overpopulation occurs when a population of a species exceeds the carrying capacity of its ecological niche. Overpopulation is a function of the number of individuals compared to the relevant resources, such as the water and essential nutrients they need to survive. It can result from an increase in births, a decline in mortality, an increase in immigration, or an unsustainable biome and depletion of resources

Indicators of over population

1.      High population density

2.      High level of illiteracy

3.      Low science and technology

4.      Vulnerability of natural disaster

5.      Rapid increase of rural population,

6.      Skewed distribution of agricultural land,

7.       Lack of development of non- agricultural sector,

8.      Lack of social development, and

Causes of overpopulation
Decline in the Death Rate: At the root of overpopulation is the difference between the overall birth rate and death rate in populations. If the number of children born each year equals the number of adults that die, then the population will stabilize. Talking about overpopulation shows that while there are many factors that can increase the death rate for short periods of time, the ones that increase the birth rate do so over a long period of time. The discovery of agriculture by our ancestors was one factor that provided them with the ability to sustain their nutrition without hunting. This created the first imbalance between the two rates.

Better Medical Facilities: Following this came the industrial revolution. Technological advancement was perhaps the biggest reason why the balance has been permanently disturbed. Science was able to produce better means of producing food, which allowed families to feed more mouths. Medical science made many discoveries thanks to which they were able to defeat a whole range of diseases. Illnesses that had claimed thousands of lives till now were cured because of the invention of vaccines. Combining the increase in food supply with fewer means of mortality tipped the balance and became the starting point of overpopulation.

More Hands to Overcome Poverty: However, when talking about overpopulation we should understand that there is a psychological component as well. For thousands of years, a very small part of the population had enough money to live in comfort. The rest faced poverty and would give birth to large families to make up for the high infant mortality rate. Families that have been through poverty, natural disasters or are simply in need of more hands to work are a major factor for overpopulation. As compared to earlier times, most of these extra children survive and consume resources that are not sufficient in nature.

Technological Advancement in Fertility Treatment: With latest technological advancement and more discoveries in medical science, it has become possible for couple who are unable to conceive to undergo fertility treatment methods and have their own babies. Today there are effective medicines which can increases the chance of conception and lead to rise in birth rate. Moreover, due to modern techniques pregnancies today are far safer.

Immigration: Many people prefer to move to developed countries like US, UK, Canada and Australia where best facilities are available in terms of medical, education, security and employment. The end result is that those people settle over there and those places become overcrowded. Difference between the number of people who are leaving the country and the number of people who enter narrows down which leads to more demand for food, clothes, energy and homes. This gives rise to shortage of resources. Though the overall population remains the same, it just affects the density of population making that place simply overcrowded.

Lack of Family Planning: Most developing nations have large number of people who are illiterate, live below the poverty line and have little or no knowledge about family planning. Getting their children married at an early age increase the chances of producing more kids. Those people are unable to understand the harmful effects of overpopulation and lack of ignorance prompts them to avoid family planning measures.

Negative effects of Overpopulation.

(i)                 Led to the lack of employment opportunities (unemployment)

(ii)               High exploitation of the available resources

(iii)             Led to the shortage of food

(iv)             Causes for the spread of diseases due to the high number of people in an area.

(v)               Unemployment to the people

(vi)             Poor standard of living and health to the people

(vii)           Lead to the over utilization of resources

(viii)         High number of people  influence environmental pollution and degradation

(ix)             Water shortage

(x)               Depletion of resources

(xi)             Conflict over scarce resources

(xii)           Increased in evils and crime

(xiii)         Easy and frequent of outbreak of diseases

(xiv)         Prevalence unemployment

Positive impact of over population.

(1)   Availability of labor, both skilled and uncalled labor. 

(2)   May lead to the advancement of science and technology.

(3)   Effective utilization of the available resources.

(4)   Presence of market to all goods, due to the high population in relation to the demand

(5)   Increase of technology

UNDERPOPULATION

Under population refers to the low number of people in an area. 

 Indicators of under population

1.      Low population growth rate

2.      The country experience high life expectancy

3.      High DGP

4.      Well developed technology an science

5.      Rare natural disaster

6.      Small rural urban ratio

Causes of under population

1.      Low birth rate and fertility rate

2.      Birth control measures

3.      Poor economy

4.      Increased death rate

5.      High emigration

6.      Poverty and economic hardship

Negative effects of under population

(1)   Led to the under utilization of resources

(2)   Cause to the shortage of manpower.

(3)   Inadequate of market

(4)   There is uneven distribution of population

Positive effects of under population

1.      No environmental pollution and degradation on under population

2.      Availability of employment

3.      Abundance resources

4.      Low pressure on social amenities

5.      Low evils and crimes

6.      Adequate planning

Why the Global Population Over Increasing

The global population is increasing because of the following Rescans.

(1)   Economic factor. In LDCs most of the people recognize that children can be a source of labor in the farms, small trade, for earning money.

(2)   Social factor. Little use of birth control due to the low education, ignorance and negligence (especially in LDCs). Some tribes take as prestige in having many children, such that having 6 – 10 children in a family is normal. Early marriage (can be for traditional or Religion). Traditional beliefs and religion beliefs they condemns for the use of modern methods of Birth control (e.g. the use of condom)

(3)   Political factor. Government failing to finance family palming programs due to the poor economic level.

Factors Influencing On Rapid Population Growth/Increase.

1. Fertility rate. Where there is high fertility there is high population growth like in Kenya. This is due to the sex preferences, polygamist, and early marriage.

2. Low mortality rate. Where there is low mortality rate, there is high population growth and where there is high mortality, there is low population growth.

3. Immigration. In flow of people from one place or country may lead to population growth.

4. Cultural beliefs like, Sex preferences, many children as a sign of prestige, early marriage, Polygamist, Naming of Relatives in all they influence rapid population increase.

5. Health services. Improved health service has led to the decline in death rate. The life expectancy has been increasing and impact mortality rate has declined leading for the increase of fertility.

6. Availability of food. Presence of enough food, people increase reproductive capacity in the presence of food because people may not be worried to feed a high population hence increasing in reproduction. 

7. Modernization. Early marriage and improved nutrition to the youth they became parents very early and hence they start getting children. 

8. Religion. Some religions do not accept artificial method of birth control, saying that, they are quite abominable before God and hence they encourage or advocate natural methods abstention sex, which are less effective in the birth capacity.

9. Economic factor. Due to poverty people like to have many children so that, they can provide chap labor. This is a common among the Nyamwezi, Ruita, Kinongo, and the Sukuma (not now days) in Tanzania

10. Political factor. Poor policy in family planning with poor imprementation.

Qn:  (i) Assess for the advantages of population increase (rapid population growth).  

        (ii) Discuss for the short coming of rapid population growth / population increase.

Impact of high Population Growth

A growing population cab be an “asset” or a “liability” that is it can be positive or negative impact as fallows;

Positive Impact

(1)    Provide people for utilizing Resources

(2)    Encourage improvement of science and technology – In agriculture, fishing etc.

(3)    Population enhances market for commodities.

(4)    Enhance trading activities etc.

Negative Impacts

(i)                 Population growth led to the intensive exploitative of Natural Resources.

(ii)               Lead to the soil erosion through farming activities and settlement establishment.

(iii)             Increase environmental pollution due to high pressure on the area 

(iv)             Increase of crimes

(v)               Increase number of Beggars e.g. in towns.

(vi)             Lead to the inadequate of social services like education, water supply, Medical services.

(vii)           Spread of diseases both, STD’s and communicable diseases.

(viii)         Scarcity of land (shortage of land).

(ix)             Shortage of food

Qn. Rapid population growth in Tanzania it can therefore lead to the impact on Natural Resources? Discuss.

POPULATION PRESSURE

Population pressure is the same as population increase, high population growth, over population in a particular land.

Factor for population pressure (increase) in a place

a.       Availability fertile soil

b.      Availability of minerals

c.       Availability of social services

d.      High fertility rate

e.       Scarcity of Arable land

f.       Poor police of population control.

Impacts of population pressure (Refers to the effects of overpopulation)

(i)     Lead to inadequate in social services

(ii)   Lead to unemployment.

(iii) It can cause deforestation

(iv) Can cause to the outbreak disease.

(v)   Lead to the shortage of resources

(vi)  Cause for environmental pollution and destruction