Food Chain Gizmo Activity WS
Name:
Vocabulary: consumer, ecosystem, energy pyramid, equilibrium, food chain, population, predator, prey,producer
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
The Food Chain Gizmo shows a food chain with hawks, snakes, rabbits, and grass. In this simulation, thehawks eat
snakes, the snakes eat rabbits, and the rabbits eat grass.
1. Producers are organisms that do not need to eat other organisms to obtain energy.
A. Which organism is a producer in this food chain?
The grass is a producer.
B. Where does the producer get its energy?
The grass gets its energy from the sun.
2. Consumers must eat other organisms for energy. Which organisms are consumers in this food chain?
The rabbit, snakes, and hawk
Gizmo Warm-up
The SIMULATION pane of the Gizmo shows the current population, or number, ofeach
organism in the food chain.
1. What are the current populations of each organism?
Hawks: 34 Rabbits: 2070
Snakes: 230 Grass: 27300
2. Select the BAR CHART tab, and click Play ( ). What do you notice about each
population as time goes by?
Some of the species decrease in the percentage of balance
If populations don’t change very much over time, the ecosystem is in equilibrium.
3. Notice the populations decrease as you go from the bottom of the food chain to the top. Why do you thinkthis is so?
Because they depend on the lower levels of the food chain to survive
This diagram, showing decreasing populations at each level, is called an energy pyramid.
, Activity A: Get the Gizmo ready:
Predator-prey ● Click Reset ( ).
relationships ● Check that the BAR CHART tab is selected.
Question: Predators are animals that hunt other animals, called prey. How do predator and preypopulations affect
one another?
1. Observe: Run the Gizmo with several different starting conditions. You can use the + or – buttons to add orremove
organisms, or you can choose Diseased from the dropdown lists.
2. Form hypothesis: How do you think predator and prey populations affect one another? (Write your
hypothesis in the “If, then, because…” format.)
If there are more prey populations then the predator population will grow as well.
3. Predict: Based on your hypothesis, predict how changing the rabbit population will affect the other
organisms at first. Write “Increase” or “Decrease” next to each “Prediction” in the table.
Change Grass Snakes Hawks
Prediction: More grass Prediction: Snakes will Prediction: Hawks will
will be consume them consume the
Doubling rabbit consumed snakes
population Result: Grass Result: Snake Result: Hawk
population population population
decreased increased increased
Prediction: Less grass Prediction: Snake Prediction: Hawks will
will be population will have less food
consumed so decrease dueto and the
the grass the lack of population will
Halving rabbit population rabbits decrease as
population will grow well.
Result: Grass Result: Decrease in Result: Hawk
population Snake population
increased population inccreased
4. Test: Add rabbits until the population is about twice as large as it was (200% of balance). Click Play, and then Pause
( ) after approximately ONE month. Next to each “Result” line in the table, write “Increase” or“Decrease.” Click
Reset and then halve the rabbit population (50% of balance). Record the results for this experiment in the table as
well.
A. How did doubling the rabbit population affect the grass, snakes, and hawks at first?
It increased the snake and hawk population first then balanced out.
B. How did halving the rabbit population affect the grass, snakes, and hawks at first?
Name:
Vocabulary: consumer, ecosystem, energy pyramid, equilibrium, food chain, population, predator, prey,producer
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
The Food Chain Gizmo shows a food chain with hawks, snakes, rabbits, and grass. In this simulation, thehawks eat
snakes, the snakes eat rabbits, and the rabbits eat grass.
1. Producers are organisms that do not need to eat other organisms to obtain energy.
A. Which organism is a producer in this food chain?
The grass is a producer.
B. Where does the producer get its energy?
The grass gets its energy from the sun.
2. Consumers must eat other organisms for energy. Which organisms are consumers in this food chain?
The rabbit, snakes, and hawk
Gizmo Warm-up
The SIMULATION pane of the Gizmo shows the current population, or number, ofeach
organism in the food chain.
1. What are the current populations of each organism?
Hawks: 34 Rabbits: 2070
Snakes: 230 Grass: 27300
2. Select the BAR CHART tab, and click Play ( ). What do you notice about each
population as time goes by?
Some of the species decrease in the percentage of balance
If populations don’t change very much over time, the ecosystem is in equilibrium.
3. Notice the populations decrease as you go from the bottom of the food chain to the top. Why do you thinkthis is so?
Because they depend on the lower levels of the food chain to survive
This diagram, showing decreasing populations at each level, is called an energy pyramid.
, Activity A: Get the Gizmo ready:
Predator-prey ● Click Reset ( ).
relationships ● Check that the BAR CHART tab is selected.
Question: Predators are animals that hunt other animals, called prey. How do predator and preypopulations affect
one another?
1. Observe: Run the Gizmo with several different starting conditions. You can use the + or – buttons to add orremove
organisms, or you can choose Diseased from the dropdown lists.
2. Form hypothesis: How do you think predator and prey populations affect one another? (Write your
hypothesis in the “If, then, because…” format.)
If there are more prey populations then the predator population will grow as well.
3. Predict: Based on your hypothesis, predict how changing the rabbit population will affect the other
organisms at first. Write “Increase” or “Decrease” next to each “Prediction” in the table.
Change Grass Snakes Hawks
Prediction: More grass Prediction: Snakes will Prediction: Hawks will
will be consume them consume the
Doubling rabbit consumed snakes
population Result: Grass Result: Snake Result: Hawk
population population population
decreased increased increased
Prediction: Less grass Prediction: Snake Prediction: Hawks will
will be population will have less food
consumed so decrease dueto and the
the grass the lack of population will
Halving rabbit population rabbits decrease as
population will grow well.
Result: Grass Result: Decrease in Result: Hawk
population Snake population
increased population inccreased
4. Test: Add rabbits until the population is about twice as large as it was (200% of balance). Click Play, and then Pause
( ) after approximately ONE month. Next to each “Result” line in the table, write “Increase” or“Decrease.” Click
Reset and then halve the rabbit population (50% of balance). Record the results for this experiment in the table as
well.
A. How did doubling the rabbit population affect the grass, snakes, and hawks at first?
It increased the snake and hawk population first then balanced out.
B. How did halving the rabbit population affect the grass, snakes, and hawks at first?
