Human Population Dynamics

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Human Population Dynamics
A review of the CAPT Embedded Task
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What is a population?
Aerial census for African buffalo in the
Serengeti of East Africa
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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
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What population is listed below? What is their
habitat?
Aerial census for African buffalo in the
Serengeti of East Africa
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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.
Aerial census for African buffalo in the
Serengeti of East Africa
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Population Growth
Numbers of organisms in a population can go up,
down, or stay constant over time.
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?
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Factors such as food availability, predators,
parasites, catastrophic events, competition
from other species, Migration habitat depletion
will all affect population size.
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Population Growth Patterns
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
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Population Growth Patterns
In a population growing exponentially, the birth
rate is higher than the death rate.
Exponential growth
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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
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Population Growth Patterns

• What is the carrying capacity of the population
  on the right?
• About how many days did it take for the
  population to reach carrying capacity?
• Which of the following is probably NOT a reason
  the population reached and maintained a plateau?
• a. limits in food supply
• b. competition with other species
• c. competition for space
• d. a major storm

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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 supply
• b. competition with other species
• c. competition for space

d. a major storm would probably not cause a
population to maintain its size
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Logistical vs. Exponential
Below is a graph of human population growth over
the last 8000 years.
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Logistical vs. Exponential
Have humans demonstrated logistical or
exponential growth?
What are some factors that have caused the
human population to skyrocket in the past 200
years?
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Logistical vs. Exponential
Humans have demonstrated exponential growth.
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)
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Human Population Growth
Although the human population as a whole is
growing at an amazing rate, different populations
of people are growing at different rates.
We can compare different countries to see these
differences.
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In this activity we will compare three different
countries
United States
Afghanistan
Italy
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Population Pyramids
To the right is a population pyramid based on a
make-believe population.
To compare different countries populations, we
can use a population pyramid.
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Population Pyramids can
Compare males vs. females in a population
Compare different age groups in a population
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Lets review...

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

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

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

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Lets review...

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

1. 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.

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Lets review...

• 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.
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So back to our previous question. How do these
three countries compare?
United States
Afganistan
Italy
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U.S. vs. Afghanistan

• Afghanistan

• United States

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Now, lets 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.
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Now, lets compare countries again
Based on these graphs, what is one issue that
each country will have to face in the future??
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Now, lets 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.
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Now, lets 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.
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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?
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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 whos
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.
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Now lets look at Italy
What are some issues that Italians face in the
future?
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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.

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Summary test yourself
To 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?
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Summary answers

• FRANCE
• 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?
• What is a major difference between the two
  populations in terms of life expectancy?
• France has many more people growing into their
  80s and even 90s 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.
• One country is growing exponentially. Which one?
• (Not this one.)

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Summary answers

• KENYA
• 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.
• What is a major difference between the two
  populations in terms of life expectancy?
• Kenya has many fewer people growing into their
  70s and even 80s 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.
• One country is growing exponentially. Which one?
• Kenya is definitely growing exponentially.

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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/