Student Exploration: Rabbit Population by Season
Vocabulary: carrying capacity, density-dependent limiting factor, density-independent limiting
factor, limiting factor, population, population density
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Suppose you had a pet rabbit. What would the rabbit need to stay alive and healthy?
• In order for the rabbit to stay alive and healthy, it would need water, food, and an
appropriate environment to live in.
2. A female rabbit can give birth to over 40 baby rabbits a year. Suppose all of her offspring
survived and reproduced, all of their offspring survived and reproduced, and so on. If that
happened, in only eight years the mass of rabbits would exceed the mass of Earth!
So, why aren’t we overrun with rabbits? What keeps the rabbit population in check?
• We are not overrun with rabbits because of the food chain. Rabbits have many
predators, and because of these predators the rabbit population is constantly leveling
off with births and deaths. So, predators and the food chain are what keeps the
rabbit population in check.
Gizmo Warm-up
A population is a group of individuals of the same
species that live in the same area. The size of a
population is determined by many factors. In the Rabbit
Population by Season Gizmo™, you will see how
different factors influence how a rabbit population grows
and changes.
1. Select the BAR CHART tab. What is the approximate
size of the initial rabbit population?
• The approximate size of the initial rabbit
population is 50.
2. Select the TABLE tab. Click Play ( ), and allow the simulation to run for one year.
A. In which season did the rabbit population increase the most?
o During the spring season, the rabbit population increased the most due to the
nice weather conditions, which call for good vegetation for the rabbits to
consume.
B. In which season did the rabbit population increase the least?
o During the winter season the rabbit population decreased due to the cold
weather conditions, which limited the rabbits chances of survival because
there was not a large food supply available for them.
Activity A: Get the Gizmo ready:
Carrying capacity • Click Reset ( ).
Question: What determines how large a population can grow?
, 1. Think about it: A limiting factor is any factor that controls the growth of a population. What
do you think are some of the limiting factors for the rabbit population?
• Some of the limiting factors for the rabbit population are, the weather conditions, food
availability, predator populations, and diseases.
2. Run Gizmo: Select the DESCRIPTION tab. Set the Simulation speed to Fast. Select the
GRAPH tab. Click Play, and allow the simulation to run for at least 10 years. (Note: You can
use the zoom controls on the right to see the whole graph.)
A. Describe how the rabbit population changed over the course of 10 years.
o Over the course of 4 years, the rabbit population increased. The next 6 years,
the population size stayed roughly the same.
B. What pattern did you see repeated every year?
o Every year, the population would reach a peak, and then drop the following
year, and then reach a new/higher peak.
C. How could you explain this pattern?
o This pattern shows, and proves, that rabbits because of the limiting factors
that keep the population in check don’t overrun the earth.
3. Analyze: The carrying capacity is the maximum number of individuals of a particular
species that an environment can support. All environments have carrying capacities.
A. What is this environment’s approximate carrying capacity for rabbits? (Note: Average
the summer and winter carrying capacities.
o This environment’s approximate carrying capacity for rabbits are between
350-450 rabbits. This is because the exact carrying capacity will vary in size.
B. When did the rabbit population reach carrying capacity? Explain how you know.
Get the Gizmo ready:
Activity B:
• Click Reset.
Density-dependent
• On the SIMULATION pane, make sure Ample is
limiting factors
selected for the amount of LAND available.
o The rabbit population reached carrying capacity during the fourth year of the
10 years we set.
Introduction: Population density is the number of individuals in a population per unit of area.
Some limiting factors only affect a population when its density reaches a certain level. These
limiting factors are known as density-dependent limiting factors.
Question: How does a density-dependent limiting factor affect carrying capacity?
1. Think about it: What do you think some density-dependent limiting factors might be?
• Some density-dependent limiting factors might be, disease, food shortages,
predation, and competition.
2. Predict: How do you think the amount of land available will affect the rabbit population?
• The amount of land available will affect the rabbit population because if the rabbits
were to live in a more spread out area, in which they would not be in close contact
Vocabulary: carrying capacity, density-dependent limiting factor, density-independent limiting
factor, limiting factor, population, population density
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Suppose you had a pet rabbit. What would the rabbit need to stay alive and healthy?
• In order for the rabbit to stay alive and healthy, it would need water, food, and an
appropriate environment to live in.
2. A female rabbit can give birth to over 40 baby rabbits a year. Suppose all of her offspring
survived and reproduced, all of their offspring survived and reproduced, and so on. If that
happened, in only eight years the mass of rabbits would exceed the mass of Earth!
So, why aren’t we overrun with rabbits? What keeps the rabbit population in check?
• We are not overrun with rabbits because of the food chain. Rabbits have many
predators, and because of these predators the rabbit population is constantly leveling
off with births and deaths. So, predators and the food chain are what keeps the
rabbit population in check.
Gizmo Warm-up
A population is a group of individuals of the same
species that live in the same area. The size of a
population is determined by many factors. In the Rabbit
Population by Season Gizmo™, you will see how
different factors influence how a rabbit population grows
and changes.
1. Select the BAR CHART tab. What is the approximate
size of the initial rabbit population?
• The approximate size of the initial rabbit
population is 50.
2. Select the TABLE tab. Click Play ( ), and allow the simulation to run for one year.
A. In which season did the rabbit population increase the most?
o During the spring season, the rabbit population increased the most due to the
nice weather conditions, which call for good vegetation for the rabbits to
consume.
B. In which season did the rabbit population increase the least?
o During the winter season the rabbit population decreased due to the cold
weather conditions, which limited the rabbits chances of survival because
there was not a large food supply available for them.
Activity A: Get the Gizmo ready:
Carrying capacity • Click Reset ( ).
Question: What determines how large a population can grow?
, 1. Think about it: A limiting factor is any factor that controls the growth of a population. What
do you think are some of the limiting factors for the rabbit population?
• Some of the limiting factors for the rabbit population are, the weather conditions, food
availability, predator populations, and diseases.
2. Run Gizmo: Select the DESCRIPTION tab. Set the Simulation speed to Fast. Select the
GRAPH tab. Click Play, and allow the simulation to run for at least 10 years. (Note: You can
use the zoom controls on the right to see the whole graph.)
A. Describe how the rabbit population changed over the course of 10 years.
o Over the course of 4 years, the rabbit population increased. The next 6 years,
the population size stayed roughly the same.
B. What pattern did you see repeated every year?
o Every year, the population would reach a peak, and then drop the following
year, and then reach a new/higher peak.
C. How could you explain this pattern?
o This pattern shows, and proves, that rabbits because of the limiting factors
that keep the population in check don’t overrun the earth.
3. Analyze: The carrying capacity is the maximum number of individuals of a particular
species that an environment can support. All environments have carrying capacities.
A. What is this environment’s approximate carrying capacity for rabbits? (Note: Average
the summer and winter carrying capacities.
o This environment’s approximate carrying capacity for rabbits are between
350-450 rabbits. This is because the exact carrying capacity will vary in size.
B. When did the rabbit population reach carrying capacity? Explain how you know.
Get the Gizmo ready:
Activity B:
• Click Reset.
Density-dependent
• On the SIMULATION pane, make sure Ample is
limiting factors
selected for the amount of LAND available.
o The rabbit population reached carrying capacity during the fourth year of the
10 years we set.
Introduction: Population density is the number of individuals in a population per unit of area.
Some limiting factors only affect a population when its density reaches a certain level. These
limiting factors are known as density-dependent limiting factors.
Question: How does a density-dependent limiting factor affect carrying capacity?
1. Think about it: What do you think some density-dependent limiting factors might be?
• Some density-dependent limiting factors might be, disease, food shortages,
predation, and competition.
2. Predict: How do you think the amount of land available will affect the rabbit population?
• The amount of land available will affect the rabbit population because if the rabbits
were to live in a more spread out area, in which they would not be in close contact
