HPG - Demographic Transitions Lesson

Demographic Transitions

Growing Like a Weed

Have you ever lost your phone? Ever wonder why something you cooked did not taste quite right? Do you try to win at video games? These are some questions you may come across in your day to day life. Did you know you can use the scientific method to help you with these questions and more?

All of this growth did not happen overnight. The population increased very slowly at first. As it increased in size, so did its rate of growth. 

Early Population Growth

Homo sapiens arose about 200,000 years ago in Africa. Early humans lived in small populations of nomadic hunters and gatherers. They first left Africa about 40,000 years ago. They soon moved throughout Europe, Asia, and Australia. By 10,000 years ago, they had reached the Americas. During this long period, birth and death rates were both relatively high. As a result, population growth was slow.

Humans invented agriculture about 10,000 years ago. This provided a more significant, more dependable food supply. It also let them settle down in villages and cities for the first time. The death rate increased because of diseases associated with domestic animals and crowded living conditions. The birth rate increased because there was more food and settled life offered other advantages. The combined effect was continued slow population growth.

Demographic Transition

Major changes in the human population first began during the 1700s in Europe and North America. First death rates fell, followed somewhat later by birth rates.

It wasn’t long before birth rates started to fall as well in Europe and North America. People began having fewer children because large families were no longer beneficial for several reasons. As child death rates fell and machines did more work, farming families no longer needed to have as many children to work in the fields. Laws were passed that required children to go to school. Therefore, they could no longer work and contribute to their own support. They became a drain on the family’s income. Eventually, birth rates fell to match death rates. As a result, population growth slowed to nearly zero.

Several advances in science and technology led to lower death rates in 18th century Europe and North America: New scientific knowledge of the causes of disease led to improved water supplies, sewers, and personal hygiene. Better farming techniques and machines increased the food supply. The Industrial Revolution of the 1800s led to new sources of energy, such as coal and electricity. This increased the efficiency of the new agricultural machines. It also led to train transport, which improved the distribution of food. For all these reasons, death rates fell, especially in children. This allowed many more children to survive to adulthood, so birth rates increased. As the gap between birth and death rates widened, the human population grew faster.

Demographic Transitions Stages Activity

Recent Population Growth

	At one time, scientists predicted that all human populations would pass through the same demographic transition as Europe and North America. However, now they are not so sure. Death rates have fallen throughout the world. No country today remains in Stage 1 of the transition. However, birth rates are still high in many poor countries. These populations seem to be stuck in Stage 2. Some examples would be the African countries of Angola and Ethiopia. The population pyramid for Angola in 2017 is shown to the left.
	Many other countries have shifted to Stage 3 of the transition. Birth rates have started to fall. As a result, population growth is slowing. An example is Mexico. Its population pyramid for 2016 is shown, and it reflects a recent fall in the birth rate. Mexico's economy may not be fully developed but the country is a good example of an emerging market economy. How do you know the birth rate is slowing down?
	Most developed nations have entered Stage 4. However, keep in mind that some developed countries can be in stages 3 and 4.  The population pyramid for Sweden in 2017 is an example. The birth rate has been low for many years in Sweden. Therefore, the rate of population growth is near zero.
	In some countries, birth rates have fallen even lower than death rates. As a result, their population growth rates are negative. In other words, the populations are shrinking in size. These populations have top-heavy population pyramids, like the one for Italy shown below. This is a new stage of the demographic transition, referred to as Stage 5. You might think that a negative growth rate would be a good thing. In fact, it may cause problems. For example, growth-dependent industries decline. Supporting the large aging population is also a burden for the shrinking younger population of workers.

Let's Recap by viewing the video below:

Demographic Transitions Challenge Activity

Before You Go, You Need To Know

The following key points are from this explore section of the lesson. You must know the following information before moving to the next lesson. This is just a summary of the key points.

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