Food Chain Bio 1assigment

ASYNCHRONOUS CLASS – Food Chain
Learning Objectives:
 Classify organisms as producers or consumers.

 Observe a food chain in equilibrium.
 Determine how one organism affects others in a food chain.
Lesson Overview
The Food Chain Gizmo shows a hypothetical food chain in which hawks eat snakes, snakes eat
rabbits, and rabbits eat grass. You can manipulate the population of each organism and the
resulting effects on the populations of other organisms can be observed over time.
The Student Exploration sheet contains two activities and an extension:

Activity A – Students explore how changing one population in the food chain
affects the others.
Activity B – Students observe the long-term changes that result from major
disturbances to the food chain
Extended Learning
Please logon to https://www.explorelearning.com and use your class code to

enroll.
Launch The Food Chain Gizmo and complete Tasks A, B and extended learning.
Please reflect on your understanding by completing the worksheet.

Name: ______________________________________ Date: ________________________
Student Exploration: Food Chain

Vocabulary: consumer, ecosystem, energy pyramid, equilibrium, food chain, population,
predator, prey, producer
Gizmo Warm-up
The SIMULATION pane of the Gizmo shows the current population,
or number, of each organism in the food chain.
1. What are the current populations of each organism?
Hawks: __34___ Snakes: __230___ Rabbits: __2070___

Grass: __27300___
2. Select the BAR CHART tab, and click Play ( ). What do you
notice about each population as time goes by?
_________________________________________________________________________
If populations don’t change very much over time, the ecosystem is in equilibrium.
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 prey populations affect one another?
1. Observe: Run the Gizmo with several different starting conditions. You can use the + or –
buttons to add or remove organisms, or you can choose Diseased from the dropdown lists.
2. Form hypothesis: How do you think predator and prey populations affect one another?
___If the predators are higher than normal, the prey populations will decrease in order to
sustain the amount of
predators._________________________________________________________________
_____
_________________________________________________________________________
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

Doubling Prediction: Decrease Prediction: Increase Prediction: Increase
rabbit
population Result: Decrease Result: Increase Result: Increase
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?
______The grass population plummeted down, while the snakes and hawks rose up
a little._____________________________________________________________
B. How did halving the rabbit population affect the grass, snakes, and hawks at first?
_____The grass went up but the snakes and hawks went down because there was
not enough
food.______________________________________________________________
5. Test: Click Reset. Try each experiment with the Gizmo. Record each result after one month.
A. How did increasing the snakes affect the grass? _____The grass increases
rapidly._______________________
Explain why: _____The snakes eat more rabbits which were eating the grass, there
are less grass consumers so more
grass.___________________________________________________
___________________________________________________________________
B. How did increasing the hawks affect the rabbits? ____________________________

The rabbits went up.
Explain why: _____The hawks would eat the snakes, so there are less snakes so the
rabbit would not have any
predators.___________________________________________________
___________________________________________________________________
6. Draw conclusions: In general, what effect did removing prey have on predators? _________
The population of the predator would

decrease._________________________________________________________________
________
What effect did removing predators have on prey? ______The population of the prey would
increase.___________________________
_________________________________________________________________________
Activity B: Get the Gizmo ready:
Long-term  Click Reset.
changes  Select the GRAPH tab.
Question: An ecosystem is a group of living things and their physical environment. How
do ecosystems react to major disturbances?
1. Observe: Kill off most of the hawks using the – button, and then click Play. Observe the
GRAPH for about 12 months, and then click Pause. What happens?
____The snakes go up and the increase in demand of food, makes the rabbits go down. As
the hawks began to recover from the loss, the other animals in the ecosystem were also
getting back to their usual
numbers.__________________________________________________________________
___
_________________________________________________________________________
2. Analyze: Explain why you think the population of each organism changed the way it did.
(Use extra paper if necessary.)
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
3. Experiment: Click Reset. Try making other changes to the ecosystem. Use the + or –
buttons, or choose Diseased from the dropdown lists. Click Play and observe for at least 12
months. Record what happens on another sheet of paper or in your notes.
4. Summarize: Give at least one example of each of the following:
A. A major disturbance that the ecosystem was able to recover completely from.
___________________________________________________________________
B. A major disturbance that caused the ecosystem to stabilize at a new equilibrium.
___________________________________________________________________
C. A major disturbance that caused the ecosystem to completely collapse.
___________________________________________________________________
D. (Challenge) A major disturbance that almost caused a total collapse, but that the
ecosystem was able to recover from eventually.
___________________________________________________________________
Extend your thinking: In North America, many top predators, such as wolves, have been driven
nearly to extinction. What effect do you think this has on their main prey, deer?

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ASYNCHRONOUS CLASS – Food Chain

 Classify organisms as producers or consumers.

The Student Exploration sheet contains two activities and an extension:

Please logon to https://www.explorelearning.com and use your class code to

Please reflect on your understanding by completing the worksheet.

Student Exploration: Food Chain

1. What are the current populations of each organism?

Hawks: 34_ Snakes: 230_ Rabbits: 2070_

Activity A: Get the Gizmo ready:

Change Grass Snakes Hawks

B. How did increasing the hawks affect the rabbits? ____________________________

The population of the predator would

4. Summarize: Give at least one example of each of the following:

B. A major disturbance that caused the ecosystem to stabilize at a new equilibrium.

C. A major disturbance that caused the ecosystem to completely collapse.

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