The Agricultural revolution was the time when human beings first domesticated plants and animals and no longer relied entirely on hunting and gathering. The industrial revolution was a series of improvements in industrial technology that transformed the process of manufacturing goods. The medical revolution was medical technology invented in Europe and North America that is diffused to poorer countries of Latin America, Asia, and Africa. Improved medical practices have eliminated many of the traditional causes of death in poorer countries and enabled more people to live longer and healthier lives. Zero Population Growth (ZPG) is a decline of the total fertility rate to the point where the natural increase rate equals zero.
Population Pyramids - Population pyramids are a means of displaying a country's population on a bar graph. A population pyramid normally shows the percentage of the total population in 5-year age groups, with the youngest group at the bottom and oldest at the top. The dependency ratio in a country is the number of people who are too young or old to work compared to the number of people in their productive years. The sex ratio is the number of males per hundred females in the population.
Sub-Topics:
There are four stages of demographic transition identifiable, each which can be associated with a corresponding population pyramid. These stages are:
- Stage One: Low Growth- crude birth and death rates varied considerably from one year to the next and from region to another, but over the long term they were roughly comparable, at very high levels. As a result, the NIR was basically non existent and Earth's population was virtually the same, at around half a million. During most of this period, people depended on hunting and gathering for food. When food was easily obtained, a region's population increased, but it declined when people were unable to locate enough animals or vegetation nearby. The escalated population growth around 8,000 B.C. was caused by agricultural revolution. By growing plants and raising animals, humans created larger and more stable sources of food, which transpired to more people surviving. Today, no county remains in this stage.
- Stage Two: High Growth- in this stage, the crude death rate suddenly plummets while the crude birth rate remains the same as it was in stage one. Because of the large disparity between the CDR and the CBR, the NIR in turn, becomes very high and population grows exponentially. Countries began the initiation of stage two after the conclusion of the Industrial Revolution. This revolution made huge improvements in industrial technology, with inventions such as the steam engine, mass production, and powered transportation. New machines helped farmers increase agricultural production and feed the rapidly growing population. The factories provided places of employment and enough food for industrial workers. The wealth that resulted from the Industrial Revolution was used to improve sanitation and personal hygiene. The improved standards of living allowed for people to be more healthy and therefore live longer. Countries in Europe and North America entered this stage in the 1800's, while most other countries in Africa, Asia, and Latin America didn't witness this movement until 1950. The medical revolution improved medical practices and suddenly put an end to many of the traditional and common causes of death in lower developed countries.
- Stage Three: Moderate Growth- When the CBR begins to drop drastically, a country moves into stage three. The CBR remains to drop, but at a much less rate than in stage two. However, the rate of natural increase is more modest in countries in stage three than in those in stage two because the gap between the CBR and CDR narrows. European and North American countries generally ,moved from stage two to stage three during the first half of the twentieth century, when most countries in Asia and Latin America have just made the transition in recent years. And still, most of African countries remain in stage two. Economic changes in stage three societies force people to produce fewer offspring. These people are more apt to live in cities as opposed to in the countryside, as they now work in offices, shops, or factories instead of being the pre-accustomed farmer. So essentially, having numerous children isn't a positive asset in the minds of parents.
- Stage Four: Low Growth- A country reaches stage four of the demographic transition when the CBR declines to the point where it equals the CDR, and the NIR is approaching zero. This condition in known as zero population growth (ZPG). Increasingly, women in stage four societies enter the labor force rather than remaining a "stay-at-home" mother. Several Eastern European countries, most notably Russia, have negative NIR's, meaning that the number of deaths exceeds the number of births. Eastern Europe's relatively high death rates and low birth rates can be accredited to Communist rule. Higher death rates are a result of poor pollution control and low birth rates are a direct correlation to smarter family planning. (Low Growth from 1970's to today)
Details:
The article below describes the great change in sex ratio in Delhi, India from 2008 to now.
The video below consists of further explanation of population pyramids and their relation to development of a specified country.
No comments:
Post a Comment