Human Population Dynamics

A review of the CAPT Embedded Task

Aerial census for African buffalo in the Serengeti of East Africa

What is a population?

Aerial census for African buffalo in the Serengeti of East Africa

A population is a group of organisms living in the same habitat that belong to the same species.

Aerial census for African buffalo in the Serengeti of East Africa

What population is listed below?What is their habitat?

Aerial census for African buffalo in the Serengeti of East Africa

What population is listed below?Below is a population of African Buffalo.

What is their habitat? They are living in the Serengeti of East Africa.

Population Growth

It should be clear that the population to the right is growing.

What are some factors that may cause a population of organisms to increase or decrease over time?

Numbers of organisms in a population can go up, down, or stay constant over time.

Factors such as:food availability, predators, parasites, catastrophic events, competition from other species, Migration habitat depletion will all affect population size.

The population at right is growing in number. When a population is growing, it is said to be growing exponentially. When a population is growing exponentially, is the birth rate higher, lower, or equal to the death rate?

Exponential growth

Population Growth Patterns

In a population growing exponentially, the birth rate is higher than the death rate.

Exponential growth

Population Growth Patterns

Population Growth Patterns

Some populations of organisms reach a plateau in their growth. This is called their carrying capacity. These populations are said to be growing with logistical growth.

carrying capacity

Population Growth Patterns1. What is the carrying capacity of the

population on the right?2. About how many days did it take for

the population to reach carrying capacity?

3. Which of the following is probably NOT a reason the population reached and maintained a plateau?a. limits in food supplyb. competition with other speciesc. competition for spaced. a major storm

Population Growth Patterns• What is the carrying capacity of the

population on the right? around 135 individuals

• About how many days did it take for the population to reach carrying capacity? about 80 days

• Which of the following is probably NOT a reason the population reached and maintained a plateau?a. limits in food supplyb. competition with other speciesc. competition for space

d. a major storm would probably not cause a population to maintain its size

Logistical vs. ExponentialBelow is a graph of human

population growth over the last 8000 years.

Logistical vs. Exponential

What are some factors that have caused the human population to skyrocket in the past 200 years?

Have humans demonstrated logistical or exponential growth?

Logistical vs. Exponential

What are some factors that have caused the human population to skyrocket in the past 200 years?

Increased technology to alter habitats (ie: skyscrapers), and medical advances (ie: antibiotics)

Humans have demonstrated exponential growth.

We can compare different countries to see these differences.

Human Population GrowthAlthough the human population as a whole is growing at an

amazing rate, different populations of people are growing at different rates.

In this activity we will compare three different countries…

United States Afghanistan Italy

Population Pyramids

To compare different countries populations, we can use a population pyramid.

To the right is a population pyramid based on a make-believe population.

Population Pyramids can…Compare males vs. females in a population

Compare different age groups in a population

Let’s review...

1. What is the most populated age group in this population?

3. About how many children in this population are under the age of 5? How many are female?

2. Predict what age group will be the most populated in 15 years.

Let’s review...

1. What is the most populated age group in this population?The most populated age group is those between 20 and 24 years in age.

2. Predict what age group will be the most populated in 15 years. Assuming that there is not a major growth period in this population in the next 15 years, the group that is currently 20-24 years old will be in the 35-39 age group.

Let’s review...

3. About how many children in this population are under the age of 5?Approximately 12.5% of the population is 0-4 years old.

How many of them are female? Looking on the left side of the pyramid in the 0-4 age bracket, about 6% of those under age 5 are female.

So back to our previous question. How do these three countries compare?

United States Afganistan Italy

U.S. vs. Afghanistan

Afghanistan

United States

Now, let’s compare countries again…What do you notice

about the populations from these countries?

Do you notice that Afghanistan has more

people in the lower age brackets?

The U.S. has more people in the middle

age bracket.

Now, let’s compare countries again…Based on these graphs, what is one issue that each country will have to face in the future??

Now, let’s compare countries again…Based on these graphs,

what is one issue that each country will have to face in

the future??

Afghanistan: Afghanistan is clearly a growing country. It has proportionally many more younger people. The country will have to supply more and more resources like food and energy for its growing population.

Now, let’s compare countries again…Based on these graphs,

what is one issue that each country will have to face in

the future??

U.S.: The U.S. is a stabilized population with little growth. It will have an aging middle class in years to come. Because the average age in the U.S. continues to rise, it may have a difficult time supporting its large number of aging citizens.

Now lets look at Italy…To the right is a population

pyramid from the year 2000 and a projected

(predicted) pyramid for the year 2025.

How does Italy differ from the first two countries?

What is expected to happen it Italy in the next 16 years?

Now lets look at Italy…To the right is a population

pyramid from the year 2000 and a projected (predicted) pyramid for the year 2025.

How does Italy differ from the first two countries? Italy is a country who’s population is on a decline.

What is expected to happen it Italy in the next 16 years? The number of young people in Italy is expected to continue to decrease over the next decade.

Now lets look at Italy…What are some issues that Italians face in the future?

Now lets look at Italy…What are some issues that Italians face in the future?

Italians face a declining population. That means a smaller work force and a shrinking population of the Italian culture and heritage.

Summary… test yourselfTo the right is a comparison of France and Kenya. Answer the following questions:

1. What is a potential concern for each country for the future?

2. What is a major difference between the two populations in terms of life expectancy? Predict why.

3. Label each country as “A growing country” or “A stable/declining country”.

4. One country is growing exponentially. Which one?

Summary… answersFRANCE

1.What is a potential concern for each country for the future?

France is a stabilized population with little growth. It will have an aging middle class in years to come. Because the average age in France continues to rise, how will the population support its large number of aging citizens?

2.What is a major difference between the two populations in terms of life expectancy?

France has many more people growing into their 80’s and even 90’s compared to Kenya.

This may be because France has better health care for the sick and elderly.

3. Label each country as “A growing country” or “A stable/declining country”. This country has a stable/declining population.

4. One country is growing exponentially. Which one?(Not this one.)

Summary… answersKENYA1.What is a potential concern for each country for the future?

Kenya clearly is a growing country. It has proportionally many more younger people than France. The country will have to supply more and more resources like food and energy for its growing population.

2.What is a major difference between the two populations in terms of life expectancy?

Kenya has many fewer people growing into their 70’s and even 80’s compared to France.

This may be because Kenya has poorer health care and fewer nursing programs for the elderly.

3. Label each country as “A growing country” or “A stable/declining country”. This country has a growing population.

4. One country is growing exponentially. Which one?Kenya is definitely growing exponentially.

You can research population pyramids, and other info having

to do with population for any country worldwide. Visit the

website below:

http://www.census.gov/ipc/www/idb/