The Demographic Transition Model [AP Human Geography Review Unit 2 Topic 5]

Summary

The video explores shifting global population trends, contrasting concerns of overpopulation with declining fertility rates in countries like the U.S. The demographic transition model is introduced, explaining how societies move through different stages of population growth based on economic and social factors. The speaker also discusses the regional population booms, particularly in sub-Saharan Africa. The epidemiologic transition model is also covered, highlighting how health and disease patterns evolve alongside population changes. The video's objective is to deepen understanding of global demographic shifts and their implications.

Takeaways

• 🌍 Global population trends are shifting: Some countries face declining fertility rates, while others experience rapid population growth.
• 🇳🇬 By 2050, Nigeria is expected to have 400 million people, overtaking the U.S. as the third most populous country.
• 📉 Sub-Saharan Africa's population is growing at 2.7% annually, faster than South Asia (1.2%) and Latin America (0.9%).
• 🏭 The demographic transition model explains population changes through five stages, linked to economic and social developments.
• 👶 Stage 1 has high birth and death rates, resulting in low population growth. Most of human history occurred in this stage.
• 💉 In Stage 2, birth rates remain high, but death rates drop due to medical advances, causing a population boom.
• 🏙️ Stage 3 sees declining birth rates due to urbanization, higher life expectancy, and changes in societal norms like gender roles.
• 🏢 Stage 4 countries, such as the U.S. and China, experience low birth and death rates, with stable or slow population growth.
• 🔄 Stage 5 speculates a declining population, as birth rates drop below death rates, with countries like Japan and Germany as examples.
• 💡 The demographic transition model works alongside the epidemiologic transition model, which explains the changing causes of death throughout the stages.

Q & A

What is the current trend in fertility rates in the U.S.?

The U.S. fertility rate has been shrinking for the last 15 years, indicating a long-term decline in the birth rate.

Why is Nigeria projected to overtake the U.S. in population by 2050?

Nigeria's population is forecasted to reach 400 million by 2050 due to its high population growth rate, which will make it the third most populous country, surpassing the U.S.

What is the demographic transition model (DTM) and its significance?

The DTM is a model that describes the transition of societies through five stages based on birth rates, death rates, and overall population growth, focusing on economic and social developments.

What characterizes Stage 1 of the demographic transition model?

Stage 1 is marked by high birth rates (CBR) and high death rates (CDR), leading to little or no natural increase (NIR). Societies in this stage lack sanitation, medicine, and have primarily agricultural economies.

How did the Industrial Revolution impact the demographic transition?

The Industrial Revolution allowed societies to move into Stage 2 by increasing urbanization, improving medicine, and boosting food production, which reduced death rates and led to population growth.

What economic changes occur in Stage 3 of the demographic transition model?

In Stage 3, birth rates begin to fall, and societies experience more job opportunities in the manufacturing (secondary sector) and services (tertiary sector), leading to urbanization and smaller family sizes.

What defines Stage 4 of the demographic transition model?

Stage 4 is defined by low birth and death rates, with the possibility of zero population growth (ZPG). This stage is characterized by economic development, increased education for women, and a focus on careers over large families.

What is the significance of the replacement rate in population growth?

The replacement rate is the total fertility rate (TFR) required to keep a population stable, typically 2.1 children per woman. If a country's TFR falls below this, the population will decrease over time.

What is the epidemiologic transition model and how does it relate to the demographic transition model?

The epidemiologic transition model explains the leading causes of death at each stage of the demographic transition, shifting from infectious diseases in early stages to degenerative diseases in later stages.

What is the potential threat posed by Stage 5 of the epidemiologic transition model?

In Stage 5, there is a re-emergence of infectious diseases due to factors like the evolution of antibiotic-resistant pathogens, increased urbanization, poverty, and globalization, leading to the potential for pandemics.

Outlines

00:00

🌍 Changing Trends in Global Population

The narrative around global population growth is shifting. The U.S. fertility rate has been declining for nearly 15 years, leading to concerns about underpopulation and potential societal collapse if people don’t have more children. Meanwhile, regions like sub-Saharan Africa are experiencing rapid population growth, adding the equivalent of France’s population every two years. The contrast between global population decline and boom brings focus to the 'demographic transition' model, a framework with five stages outlining the economic and social developments influencing population changes.

05:02

🏭 The Industrial and Medical Revolutions' Impact on Population

The Industrial Revolution ushered in Stage 2 of the demographic transition model, as countries saw a decrease in death rates while birth rates remained high, leading to population growth. Advances in medicine and agricultural productivity played significant roles. Migration patterns shifted as urbanization increased, with people moving to cities for economic opportunities. Countries like Afghanistan are currently in Stage 2, with rapidly expanding populations as seen in their population pyramids. Societies in this stage also experience improvements in medical care, agriculture, and overall economic conditions.

10:03

🏙️ Urbanization and Decreasing Birth Rates

As countries enter Stage 3 of the demographic transition model, birth rates start to decline, driven by urbanization and increased medical advancements. Families have fewer children due to economic conditions and changing cultural attitudes, particularly toward gender roles. Women gain more rights and participate more in the economy. Mexico is an example of a Stage 3 country, with its population growth slowing as more people enter their reproductive and post-reproductive years. Migration to urban areas continues as economic opportunities in the secondary and tertiary sectors increase.

💼 Economic Stability and Population Balance

Stage 4 of the demographic transition is characterized by both low birth and death rates, resulting in a low to flat natural increase rate (NIR). Economic factors like higher living costs, career focus, and delayed marriages contribute to smaller family sizes. Education for women and more job opportunities in the tertiary sector drive social changes. Countries like the U.S. and China exemplify Stage 4, with their population pyramids showing balanced age distribution. However, political policies can influence these stages, such as China’s one-child policy.

📉 Speculative Stage 5 and Population Decline

Stage 5, a speculative stage, is marked by a negative NIR, where birth rates fall below death rates, causing population decline. Countries like Japan and Germany are examples of Stage 5, where aging populations dominate their demographic pyramids. A total fertility rate (TFR) below 2.1 will lead to population decreases unless offset by migration. While migration can impact population trends, demographic indicators focus on births and deaths within a country.

🦠 The Epidemiologic Transition Model: Health and Disease

The epidemiologic transition model, closely tied to the demographic transition model, examines how causes of death shift through different stages of population development. In Stage 1, death comes from a wide range of causes, such as pestilence and famine. As societies enter Stage 2, advancements in medicine and living conditions reduce deaths from diseases and pandemics. Stage 3 sees deaths from degenerative diseases, while Stage 4 includes delaying these diseases through improved health care. In Stage 5, the reemergence of infectious diseases poses new challenges due to factors like poverty, urbanization, and global travel.

🦠 Disease Evolution and Global Challenges

Stage 5 of the epidemiologic transition model highlights the resurgence of infectious diseases due to factors like disease evolution, urbanization, and global travel. The development of antibiotic-resistant 'superbugs' and the spread of diseases in densely populated cities are major concerns. Globalization and travel also contribute to the spread of pandemics, as seen with COVID-19. Lower-income communities face greater risks due to limited access to healthcare and exposure to diseases through essential jobs. Understanding these health transitions is crucial for studying demographic trends and societal development.

Keywords

💡Demographic Transition Model (DTM)

The Demographic Transition Model (DTM) is a theoretical framework that explains changes in a country's population structure over time as it industrializes. It consists of five stages that describe the shifts in birth rates (CBR), death rates (CDR), and natural increase rates (NIR) due to social and economic developments. In the video, it is central to understanding the contrasting trends of population growth and decline across different regions of the world.

💡Stage 1

Stage 1 of the Demographic Transition Model is characterized by high birth rates (CBR) and high death rates (CDR), leading to a low natural increase rate (NIR). Societies in this stage are typically pre-industrial, with little access to modern medicine or sanitation. The video mentions that no countries remain in this stage today, as societies have progressed due to industrial and medical advancements.

💡Stage 2

Stage 2 is marked by a decline in death rates (CDR) while birth rates (CBR) remain high, resulting in rapid population growth. This stage is often associated with industrialization, improved food supply, and medical revolutions. In the video, countries like Afghanistan are cited as examples of those currently in this stage, where a growing young population indicates future population expansion.

💡Stage 3

In Stage 3 of the DTM, both birth rates (CBR) and death rates (CDR) decline, leading to more moderate population growth. This transition is often influenced by urbanization, increased education, and access to family planning. The video uses Mexico as an example, where the population growth has slowed compared to earlier stages due to changing economic and social conditions.

💡Stage 4

Stage 4 is characterized by low birth and death rates, leading to a stable or slightly fluctuating population growth rate. Economic opportunities, higher education levels, particularly for women, and increased costs of living contribute to smaller family sizes. The United States and China are given as examples of countries in this stage, where population growth has leveled out.

💡Stage 5

Stage 5 is a speculative stage where birth rates fall below death rates, resulting in a declining population. Countries such as Japan and Germany are highlighted as examples, facing challenges due to aging populations and low fertility rates. Without sufficient births or immigration, these societies may struggle to maintain their workforce and support aging populations.

💡Fertility Rate

The fertility rate refers to the average number of children a woman is expected to have in her lifetime. A fertility rate of 2.1 is considered the replacement level, needed to maintain a stable population. The video discusses declining fertility rates in countries like the U.S., which is causing concerns about potential population decline and its impact on civilization.

💡Natural Increase Rate (NIR)

The natural increase rate (NIR) is the difference between the birth rate (CBR) and death rate (CDR) in a population, excluding migration. A positive NIR indicates population growth, while a negative NIR signals decline. The video explores how various countries’ NIR changes as they transition through different stages of the demographic transition model, with countries like Japan experiencing negative NIR in Stage 5.

💡Migration

Migration refers to the movement of people from one place to another, often driven by economic opportunities or living conditions. In the demographic transition model, migration patterns shift as countries industrialize. For instance, in Stage 2, migration to urban areas increases, while in Stage 3 and 4, emigration may decrease as more economic opportunities arise within the country itself.

💡Sub-Saharan Africa

Sub-Saharan Africa is used in the video as a region experiencing a significant population boom, with a growth rate of 2.7% annually. This contrasts with regions like South Asia and Latin America, where population growth is slowing. Sub-Saharan Africa's rapid population increase is attributed to its presence in earlier stages of the demographic transition, where high birth rates persist while death rates have fallen due to medical and agricultural advancements.

Highlights

The U.S. fertility rate has been shrinking for nearly 15 years, signaling a potential population decline.

By 2050, Nigeria is forecasted to have 400 million people, surpassing the U.S. as the third most populous country.

Sub-Saharan Africa's population is growing at 2.7% annually, significantly faster than South Asia and Latin America.

Africa adds the population of France or Thailand every two years due to its rapid growth.

The demographic transition model explains population growth and decline through five stages related to societal development.

Stage one societies have high birth and death rates, with a low natural increase rate due to a lack of sanitation, medicine, and advanced agriculture.

No countries today remain in stage one of the demographic transition model, which characterized much of human history.

The Industrial Revolution moved countries into stage two, boosting population growth due to improved food surplus and medical advancements.

Countries like Afghanistan are still in stage two, experiencing population booms due to high birth rates and decreasing death rates.

Stage three sees a decrease in birth rates as urbanization and economic opportunities reduce the need for large families.

Mexico is in stage three, where population growth slows, but the population remains relatively young and expanding.

Stage four countries like the U.S. and China experience low birth and death rates, leading to stable or zero population growth.

Stage five is speculative, involving countries like Japan and Germany, where birth rates are lower than death rates, causing population decline.

In stage five, a country's total fertility rate must be above 2.1 to maintain population; below that, the population shrinks.

The epidemiologic transition model aligns with the demographic transition model, explaining the primary causes of death in each stage.

Transcripts

for most of my life I've been told that

the world is going to become

overpopulated but recently I've noticed

that the conversation around population

growth has started to change the U.S

fertility rate is actually shrinking and

has been for a while it's been falling

for the last almost 15 years now at this

point I can't emphasize this enough

there are not enough people if people

don't have more children civilization is

going to crumble mark my words but while

some countries are concerned with a

population bust there are still regions

in the world that are experiencing a

population boom according to the

economist by 2050 Nigeria is forecasted

to have 400 million people meaning it

will overtake the United States as the

world's third most populous country and

as of today sub-Saharan Africa's

population is growing at 2.7 percent a

year which is more than twice as fast as

South Asia which is at 1.2 percent and

Latin America which is at point nine

percent that means Africa is adding the

population of France or Thailand every

two years so which is is it is the

global population crashing or is it

exploding to answer this question we

have to understand the demographic

transition it's a model that has five

different stages and it focuses on

different economic and social

developments of a society in the first

stage societies have a high CBR and CDR

which actually end up creating a low nir

since the births and deaths end up

canceling each other out Societies in

this stage are traditionally lacking

sanitation medicine contraceptive and

have more of an agricultural based

society in fact the majority of people

work in subsistence agriculture which is

when people produce food for themselves

and not for sale you can see that during

this stage migration is often focused

around the search for food here people

are just trying to meet their basic

needs in fact the majority of human

history actually took place during this

stage but as of today there are no

longer any countries that are in this

stage of the demographic transition

model now once the Industrial Revolution

happened we started to see countries and

societies transition into stage two of

the demographic transition the

Industrial Revolution led to the

enclosure movement increased rates of

urbanization allowed for more

specialization in society increased

society's food surplus and allowed for

advancements to be made in medicine

which would eventually lead to the

medical Revolution Europe and North

America were one of the first regions to

enter stage two due to the diffusion of

the Industrial Revolution eventually we

saw Africa Asia and Latin America start

to transition into stage two thanks to

further diffusion of technology and due

to the medical Revolution countries in

stage two continue to have a high CBR

but they start to see their CDR decrease

which leads to a population boost as the

CBR and CDR no longer cancel each other

out during this stage societies increase

their knowledge in medicine improve

their agricultural production increase

their food surplus and lower their IMR

and CDR all of which leads to a

population boom during this stage we

also start to see increased rates of

migration to urban areas this is due to

people seeking more Economic Opportunity

is in the city in the secondary sector

of the economy and also due to the fact

that many of the subsistence

agricultural production is now shifting

over into commercial agriculture besides

people moving from rural areas to urban

areas we may also see increased

emigration as more migrants will seek

economic opportunities in core countries

or more developed countries today we can

see that countries like Afghanistan are

in stage two of the demographic

transition model as seen here in their

population pyramid notice that the

majority of Afghanistan's population is

in the pre-reproductive years and

reproductive years which shows that the

country has an expanding population

eventually countries start to move into

stage three during this stage the CBR

starts to decrease along with the CDR

continuing to decrease these changes in

both the CBR and the CDR cause the nir

now to become more modern as more people

live in the cities they no longer have

the space or the economic need for

larger families medical advancements in

society lead to a higher life expectancy

and decrease the infant mortality rate

which leads to families having less kids

we may also start to see cultural

changes in society as well such as how

people view gender roles which may often

lead to women gaining more rights in

society and being allowed to participate

more in the economy as Society starts to

develop we start to see more and more

jobs open up in the manufacturing sector

which would be part of the secondary

sector of the economy we also start to

see more jobs starting to appear in the

tertiary sector of the economy as well

these new economic opportunities also

shift migration patterns as well

traditionally we see that less people

emigrate from a country that has more

jobs in the secondary and tertiary

sector as the economy advances migrants

will stay in their own country to be

able to explore the economic

opportunities that exist at home today

we can look at Mexico as an example of a

stage three country notice that when

we're looking at Mexico's population

pyramid the middle of the pyramid is

starting to fill out more people in the

country are now in their reproductive

years and post-reproductive years we can

see that Mexico is still growing as a

country but not as fast as it would have

been if it it was in stage two next is

stage four which is defined by a low CBR

and low CDR and actually now a low to

Flat Nar here countries start to see

more economic opportunities for all

citizens higher rates of education for

women more jobs in the tertiary sector

of the economy and more intra-regional

migration during the stage countries may

experience zpg which is zero population

growth this means that the country's CBR

and CDR are essentially the same causing

the nir to be zero this demographic

shift occurs for a variety of different

reasons we can see that economically

more people are focused on their career

and start to get married later in life

which causes them to have children later

as well which of course leads to smaller

family sizes as the economy grows we

will also see the cost of living

increase which decreases the amount of

disposable income that individuals have

which will further decrease the TFR of a

society as people start to feel like

they can no longer afford to either

start a family or support a larger

culturally we start to see Society offer

more education and opportunities for

women during this stage which allow

women to play a more active role in

society and the economy this shift also

allows women to pursue their own careers

and goals instead of being seen as child

Bear all these societal advancements

help further decrease the society's CDR

and IMR as people continue to gain more

access to wealth they also gain access

to Better Health Care Services and more

nutritious foods which helps increase

the average life expectancy and decrease

the death rate today we can see that

countries like the United States and

China are good examples of a stage four

country if we look at their population

pyramids we can see that they form more

of a box shape notice that the

population spread out between the

different age cohorts and while the

countries are no longer seeing a large

population boom they are also not seeing

a large decline I do want to highlight

that sometimes the country may move

between stages due to political policy

which can either promote people to have

more children or deter people from

having children government policies such

as the one child policies are are what

helped China transition into stage four

but we'll talk about those policies more

in our unit 2 topic 7 video lastly

there's the speculative stage five which

is defined by a negative nir hear a

country's birth rate goes below the CDR

causing the country's population to

decrease countries that could be in

stage five would be Japan or Germany

notice how the majority of their

population is located in the

post-reproductive years on their

population pyramids both of these

countries have a negative nir which

means their overall population is

decreasing in order for a country to be

growing they have to have a TFR above

2.1 this is known as the replacement

rate if their TFR is below 2.1 the

population will decrease over time

remember though migration can change

this and when we're talking about the

CBR CDR and nir we are looking at births

and deaths that take place in the

country these indicators do not factor

in Immigration or emigration okay so

that's the demographic transition model

next we have to go over the

epidemiologic transition model but

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exam now the epidemiologic model goes

along with the demographic transition

model there are a couple differences but

for the most part we can use this model

to better understand the different

causes of death for each stage of the

demographic transition model stage one

is defined by pestilence famine and

death here people are going to die from

a variety of different things parasitic

diseases infectious diseases animal

attacks pandemics epidemics food

shortages dirty water you name it you

can die to it one of the most well-known

killers in this stage was actually the

bubonic play now I mentioned epidemics

and pandemics remember an epidemic is a

disease that spreads through a region or

community and a pandemic is a disease

that spreads across multiple regions

countries or possibly the world another

term that you'll want to be familiar

with is and which is a disease that

stays in a particular area and does not

spread through an entire region or

Community now when countries transition

from stage 1 to stage two we start to

see a decrease in the amount of deaths

caused by Major diseases this is due to

a variety of different factors such as

advancements in medicine an increase in

food supply and a higher standard of

living stage two is defined by less

deaths and receding pandemic during

stage two Society gains access to new

technologies that not only improve the

standard of living but also help

increase the amount of food that is

produced societies also start to eat

more nutritious food and see

improvements in sanitation as well

remember during stage two is when the

Industrial Revolution and medical

Revolution occur these events decrease

the country's CDR but like we talked

about earlier in the video do not

decrease the CBR right away which leads

to societies to have a high nir as

societies continue to advance they

eventually enter stage three which is

defined by degenerative diseases here

people start to live longer and start to

die from diseases which are human caused

or caused by time for example heart

attacks from eating unhealthy food or

different types of cancer next to stage

four which is defined by fighting

degenerative diseases and longer life

expectancy this is when medical

advancements in society can delay

degenerative diseases which increases a

society's life expectancy during the

stage most individuals will continue to

improve their diets with more nutritious

foods and make better health decisions

like not choosing to use different drugs

but at the same time we can see that

these different advancements in society

can also promote negative habits as well

such as living a more sedentary

lifestyle or eating more junk food which

may lead to new health problems for

individuals such as obesity or diabetes

the last stage is stage five and it's

defined by the re-emergence of

infectious disease during this stage

parasitic diseases and infectious

diseases become more prevalent again

this can happen for a variety of

different reasons the first is the

evolution of diseases this is when a

society sees different diseases mutate

and develop resistance to antibiotics we

can see that over time as Society

continues to use antibiotics we may see

the development of superbugs which are

different strains of bacteria or viruses

that are resistant to most antibiotics

the next reason is an increased rate of

poverty and urbanization As Cities

become larger and more densely populated

it becomes easier for disease to spread

throughout a city and when people live

in poverty they are less likely to be

able to afford different medication and

health care services which can lead to

an increase in the CDR lastly there is

globalization when people travel around

the world they gain experiences share

ideas but also at the same time they

share germs This Global Travel and

connectivity can lead to pandemics such

as covid-19 we saw that cities that had

large international airports and densely

populated areas saw covid-19 spread

through their communities first we also

saw people who were in lower income

brackets had higher rates of covet since

they had less access to health care

services and were more likely to be

working in jobs where it was more more

likely to be exposed to the virus now

both the demographic transition model

and epidemiologic transition model are

important models for this class so

you'll want to make sure that you're

familiar with both of them all right now

you know the drill now comes the time to

practice what we have learned answer the

questions on the screen and when you're

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