Size of Population

The population of the World is increasing at the rate of 3 children per second. The growing population is largely affecting the ecosystem. This note provides information about the population status of the World and Nepal from past to present.

Summary

Things to Remember

The size of the population always keeps on changing with respect to fertility, mortality, and migration.
In 1952/54 AD, the census was conducted using internationally acceptable definition and methodology in Nepal.
The current population of the world is 7.4 billion according to the 2016 survey.
The population is the total number of people living in a particular place like village, city, country etc. at a particular time
The population of Nepal was in declining phase from 1911 to 1930 AD.
High infant mortality rate and early marriage are one of the reasons for the rapid increase in population after 1941 AD.
The population of Nepal according to the census conducted in 2011 AD is 2, 64, 94, 504.

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Subjective Questions

Q1:

Explain the fetal circulation ?

Type: Long Difficulty: Easy

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Answer: Before going through fetal circulation, we should understand the several temporary structures that enable the fetal circulation, which become change after delivery. These are:
<ol>
<li>The umbilical vein leads from the umbilical cord to the underside of the liver and carries blood rich in oxygen and nutrients. It has a branch which joins the portal vein and supplies the liver.</li>
<li>The Ductus venosus (from a vein to vein) connect the umbilical vein to the inferior venecava. At this point, the blood mixes with the deoxygenated blood returning from the lower parts of the body. Thus the blood throughout the body is at best partially oxygenated.</li>
</ol>
<ul>
<li>The foramen ovale (oval opening) is a temporary opening between the atria which allows a majority of blood entering from the inferior venecava to pass across onto the ;left atrium. The reason for this diversion is that the blood does not need to pass through the lung since it is already oxygenated.</li>
</ul>
<ol>
<li>The ductus arteriosus (from an artery to an artery) leads from the bifurcation of the pulmonary artery to descending aorta, entering it just beyond the point where the subclavian and carotid arteries leave.</li>
<li>The hypogastric arteries branch off from the internal iliac arteries and become the umbilical arteries when they enter the umbilical cord. They return blood to the placenta.</li>
</ol>
The umbilical vein carrying the oxygenated blood (80% saturated) from the placenta enters the fetus at the umbilicus and runs along the free margin of the liver. In the liver, it gives off branches to the left lobe of the liver and receives the deoxygenated blood from the portal vein. The greater portion of the oxygenated blood mixed with portal venous blood and inferior venecava and then reach to the right atrium of the heart.
In the right atrium, most of the blood (75%) is guided towards the foramen ovale by the valve of the inferior venecava and crista dividends and passes into the left atrium. Here it is mixed with small amount of venous blood returning from the lungs through the pulmonary vein. The left atrial blood is passed on through the mitral opening to the left ventricles.
Remaining lesser amount of blood (25%) after reaching the right atrium via the superior and inferior venecava passes through the tricuspid opening into the right ventricle.
During ventricular contraction, the left ventricular blood is pumped into the ascending and arch of the aorta and distributed by their branches to the heart, head , neck brain, and arms. The right ventricular blood is low oxygen content is discharged into the pulmonary trunk, the major portion of the blood passed directly through the ductus arteriousus into the descending aorta bypassing the lungs where it mixes with the blood from the proximal Aorta and only small portion is goes to lungs for 0xygen and nutrients supply for both lungs. The mixed blood of descending aorta is distributed in the whole body and most impure blood leaves the body by the two umbilical arteries to reach the placenta

Videos

Fetal Circulation

Size of Population

A population can be defined as the total number of all the organisms of a same group or species living in a particular geographical area. The population is the total number of people living in a particular place like village, city, country etcetera at a particular time. The population of any area does not remain the same, it keeps on changing with respect to time, environment, fertility, mortality and migration. We can estimate the size of the population of a particular place at a particular time.

Source: www.express.co.uk Fig: Population — _{^{Source: www.express.co.uk}}
Fig: Population

Population Size and its Growth Rate

The current population of the world is 7.4 billion according to the 2016 survey. It is the highest of all. The population of the world is increasing day by day. China covers 18.79% (according to a survey conducted on June 20, 2016, AD) of the World with the highest population in the world. The country with least population in the world is Vatican City with 839 people according to the survey conducted on July 1, 2012, AD. Talking about the history of the population of Nepal, the first census was conducted in 1911 AD until 1940 AD but, it was not systematic. But in 19525/52 AD, the census was conducted using internationally acceptable definition and methodology. But only the census of 1961 AD is accepted as the first scientific census of Nepal in terms of international standard and comparison. The given table present the total number of population from the census since 1911 AD.

Census Year (AD)	Total Population	Net Growth	Average Annual Growth Rate (%)	Population Doubling Time (Years)
1911	56, 38, 749	-	-	-
1920	55, 73, 788	-64, 961	-(0.13)	-
1930	55, 32, 574	-41, 214	-(0.07)	-
1941	62, 83, 649	7,51,075	1.16	60
1952/54	82, 56, 625	19,72,976	2.27	31
1961	94, 12, 996	11,56,371	1.64	42
1971	1, 15, 55, 983	21,42,987	2.05	34
1981	1, 50, 22, 839	34,66,856	2.26	26
1991	1, 84,91,097	34,86,258	2.08	33
2001	2, 31, 51, 423	46,60,326	2.25	31
2011	2, 64, 94, 504	33,43,081	1.35	52

In the above-given table, we can observe that the population of Nepal was decreasing up to 1930 AD. The population of Nepal was in decreasing phase from 1911 to 1930 AD. The population of Nepal in 1911 was 5.6 million whereas in 1920 the population decreased to 5.5 million. The population in 1930 was less than the population in 1920. It is believed that the reason behind the decreasing trend of this population was worldwide influenza epidemic, famine, unscientific census and heavy casualties suffered by Nepalese Army in the First World War. The census of 1920 was conducted after the First World War and the census of 1941 AD was conducted during mid- period of the Second World War in which about 2,00,000 Nepalese soldiers were recruited in the Gurkha Army. The census of 1930 AD was conducted during the time when Nepal was preparing for war with Tibet. Other reasons may be undercounting of the population during those censuses because the census enumeration prior to 1952/54 AD used to be conducted by landlord's agent. This census lacks scientific and systematic methodology and trained and supervised persons who carried out the calculation.

Source:nepaloutlook.com Fig: Population of Nepal — _{^{Source:nepaloutlook.com}}
Fig: Population of Nepal

Some reason of decrease in the population in the second and the third census are listed below,

First World War
Recruitment of Nepalese Youth to Gurkha Army
Unscientific and unsystematic methods of counting population
Famine for long period
Spread of pandemic Influenza
Due to Nepal- Tibet War

The population of Nepal started increasing from 1941 AD onwards. The population increased by 2.27% during census period from 1941 to 1952. The population of the Nepal increased by 1.64% from 1952/54 to 1961 AD. The population growth rate has crossed 2% since from 1971 to 2001 AD census. The population growth rate was 1.35% from 2001 to 2011 AD.
Here, the main reason for the increase in population was less mortality rate with persistent high fertility rate, the return of Nepalese from I and II World War and from other countries after the establishment of democracy, less spread of pandemic diseases, immigration in large number from neighboring countries like Bhutan, India, etc. The population growth rate was stable in 2011 AD as it was 1.35%. If the population of our country goes on increasing like this, the population of our country will be double in coming 52 years.

Some of the reasons for rapid increasing of population after 1941 AD are listed below,

Marriage at young age
High infant mortality rate
Low status of Women
Importance to son
High fertility rate
Immigration
Polygamy
Poverty
Superstition
Joint family
Lack of family planning

According to the population census report of 2011 AD, the demographic status of Nepal is given below,

Average population growth rate: 1.35%
TFR: 2.6
CBR: 24.3
IMR: 46
CMR: 54

This demographic data of 2011 AD is better than other censuses. As we know that, the population growth rate was less from 2001 to 2011 AD than other censuses. Education, an increase in contraceptive prevalence rate, foreign employment, public awareness, woman empowerment, the tendency of late marriage, attraction to the small and nuclear family were the reasons behind the fall of population growth rate. Some reasons behind the fall of population growth rate from 2001 AD to 2011 AD are listed below,

Some reasons behind the fall of population growth rate from 2001 AD to 2011 AD are listed below,

Increase in immigration rate due to foreign employment
Increase in contraceptive prevalence rate
Attraction of people towards small family
Marriage at suitable age
Status change of women
Acess to education and health facilities
Urbanization

Lesson

Population Situation of Nepal and Environment

Subject

Enviroment Population and Health

Grade

Grade 9

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