What is a Population?

Population be defined as the number of people or inhabitants (either the total number, or the number of a particular race or class) in a given place or location (eg. country, city, village, etc.) In biology, populations are groups of individuals belonging to the same species that live in the same region at the same time.

What is the World Population?

As of October 31, 2011, there are officially 7 billion people living on planet Earth! There’s no way to know, of course, when exactly the 7 billionth baby is born, but today is the United Nations’ best estimate. Seven billion is a hard number to imagine, but each of us counts as one of those people. If you started now to count out loud to 7 billion, how long do you think it would take you? According to National Geographic, it would take you… 200 years!
There are 7,000 different languages in the world in nearly 200 countries.
Do you know which country has the highest population? Right now it’s China with 1.3 billion people … but when you’re about 30 years old, many experts believe India’s population will surpass China’s. National Geographic also made a video on what the “typical” person on our planet looks like.
To see it click on the PLAY in the video below:

When you are about 40 years old … the population will be around 9 billion! Every second, five people are born and two people die, according to NG. By the time you finish reading this post, approximately 200 babies will have been born!
Having more people who are born than die is part of the reason why the population keeps growing. People, in general, are also living longer. Some people live longer than others, of course, but how long do you think people generally live to be? The average (meaning that if you took all the people who live less and live more and found what’s in the middle) person in the U.S. lives to be about 78 years old. In some countries in Africa, however, people aren’t expected reach their 40th birthday.
Do you think with so many people that Earth is getting crowded? Earth is, after all, 70% covered by oceans. You would think we’d be running out of space, but we’re not. National Geographic says that if all 7 billion people on the planet stood shoulder-to-shoulder, it would fill just the city of Los Angeles. We have the space, but we are stressing the world’s resources. And we need to be careful of that. There are always more people being born, and those people need to eat, drink, and use energy. But there’s only one Earth.

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Part of the problem is that our resources also aren’t distributed evenly. Experts say there is enough food produced on the planet to be able to feed everyone, but it’s not all where it needs to be. Some people have more than they need, others don’t have enough, and it’s a tough problem to solve. Estimates are that about 1 in 7 people in the world don’t have enough food. Nearly half the world lives on less than $2 a day. And while for many of us getting a drink of water or taking a bath is as easy as turning on the tap, in some parts of the world, a person can spend many hours a day in search of clean water for their family. Often, as well, nations with more wealth consume a disproportionate amount of resources per person than those in developing nations.

What are the effects of Population Growth?

Population Density:

Population density is a measurement of population per unit area or unit volume. It is frequently applied to living organisms, and particularly to humans. It is a measure of the number of organisms that make up a population in a defined area.
  • A rural area is a geographic area that is located outside of cities and towns. These areas usually have a sparse population.
  • An urban area is a geographic area that is located within towns and cities. These areas are said to have a dense population.



Human migration is the movement by people from one place to another with the intention of settling temporarily or permanently in the new location. The movement is typically over long distances and from one country to another, but internal migration is also possible. Migrations have occurred throughout human history, beginning with the movements of the first human groups from their origins in East Africa to their current location in the world.

Types of Migration:

  • Internal Migration - Moving to a new home within a state, country, or continent.

  • External Migration - Moving to a new home in a different state, country, or continent.

  • Emigration - Leaving one country to move to another (e.g., Trinidadians leaving to settle in America).

  • Immigration - Moving from one country into a new country (e.g., Germans leaving Germany to settle in Tobago for retirement).

Why do people Migrate?

There are a number of causal factors that influence people's decisions to migrate from one place to another. Migration is usually the result of push factors, which force people to move away from an area, and pull factors which attract people to move in.

  • Not enough jobs
  • Inadequate living conditions
  • Famine or drought
  • Political fear or persecution
  • Slavery or forced labour
  • Poor educational and health facilities
  • Natural disasters
  • Desire for more political or religious freedom
  • Pollution
  • Poor housing
  • Discrimination
  • High levels of crime and violence
  • War
  • Job opportunities
  • Higher wages and salaries
  • Better living conditions
  • The feeling of having more political and/or religious freedom
  • Enjoyment
  • Education
  • Better medical care
  • Attractive climates
  • Security
  • Family links
  • Industry
  • Better chances of marrying
  • Low levels of crime and violence


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Urbanization is a population shift from rural to urban areas, and the ways in which society adapts to the change. It usually results in the physical growth of urban areas, be it horizontal or vertical. The United Nations projected that half of the world's population would live in urban areas at the end of 2008.

What causes Urbanization?

Industrialization, modernization and economic opportunity cause urbanization, or an increase in the number of people moving from rural to urban areas. Urban areas offer better opportunities for employment, housing and education, and city living allows people to benefit from diversity and marketplace competition.

Effects of Urbanization:

Positive Effects
Negative Effects
* Reduced transport costs
  • Growth in industrial productions: The production in various industrial sectors like cement, iron and steel, textile, fertilizers etc., are helping in the economic growth of the country. Export increase and this forest reserve increases.
  • Growth in trade and commerce: Urbanization helps the nation's business sector. Rural people came to the urban places with their goods.
  • Development in tourism industries: People from foreign countries are attracted to good cities and towns having better transport facilities. Tourism is a good source of foreign currency for a country.
  • Improvement in Science, Culture etc.: Urban places are the meeting point of all good cultures of various localities. Education, science and technology developments take place in urban places improving the society as a whole.

  • Intensive urban growth can lead to greater poverty, with local governments unable to provide services for all people.
  • Concentrated energy use leads to greater air pollution with significant impact on human health.
  • Automobile exhaust produces elevated lead levels in urban air.
  • Large volumes of uncollected waste create multiple health hazards.
  • Urban development can magnify the risk of environmental hazards such as flash flooding.
  • Pollution and physical barriers to root growth promote loss of urban tree cover.
  • Animal populations are inhibited by toxic substances, vehicles, and the loss of habitat and food sources.
  • Unemployment and underemployment
  • Severe shortage of housing
  • Lack of public transport
  • Traffic congestion
  • Crime and violence
  • Communicable diseases are spread faster

Effects of Urbanization in Bangladesh