Hong Kong Baptist Univeristy
Department of Education Studies
Computer Modelling and Knowledge Building
Worksheet on Marine Ecology (B2) (English Version)
Name: ________________________
Student Number: ____________________
Overall Task：Build a stable marine ecosystem associated with a single food chain.
The food chain includes: (1) producer – phytoplankton; (2) primary consumer zooplankton; (3) predator and (4) top predator.
Top predator:
shark
Predators: tuner
and lancet
Primary consumer:
shrimp
Producer:
phytoplankton
Figure 1: Food web extracted from
http://media-2.web.britannica.com/eb-media/48/6548-004-4D277914.gif)
1
Hong Kong Baptist Univeristy
Department of Education Studies
Computer Modelling and Knowledge Building
Task 1: Explore the population dynamics of an ecosystem that comprises (A)
phytoplankton
1
, (B) shrimps
Before your exploration, answer the following questions：
Conjecture
1.1 Sketch a broken line graph to show how the number of shrimps and number
of phytoplankton vary with time。(discuss)
quantity
shrimp
phytoplankton
time
Reason(s): __________________________________________________
_____________________________________________________________
2
Download and save the file task1B(eng).wrld on your desktop from
http://ited.hkbu.edu.hk/wm/index-dd-2011.html/
3
Open WorldMaker 2000 at http://ited.hkbu.edu.hk/wm/index-dd-2011.html/
4
Use WorldMaker 2000open task(eng).wrld:
5
Turn on the background:
2
Hong Kong Baptist Univeristy
Department of Education Studies
Computer Modelling and Knowledge Building
1
2
3 select the region to be filled with
water
6
7
Fill the selected space with water (Follow Steps 1, 2 & 3)
Add phytoplankton and shrimps to the ecosystem.
8
How do the number of phytoplankton and the number of shrimps change with time?
Observation:
_________________________________________________________________
_________________________________________________________________
8.1
Open the graph:
Does the graph align with your prediction? Why? Discuss.
_____________________________________________________________
_____________________________________________________________
3
Hong Kong Baptist Univeristy
Department of Education Studies
Computer Modelling and Knowledge Building
8.2
The variation of the population of phytoplankton and that of shrimps are
given in Figure 2 on the last page of this worksheet.
Why the changes in number of phytoplankton and number of shrimps are
not in phase? Discuss
Reason: ____________________________________________________
9
___________________________________________________________
On the top-left hand corner, select ‘foreground’, then click the button next to
‘shrimp’
. Try to adjust the birth or death rate as shown below. Refer to the
graph, record the change in the populations of phytoplankton and shrimps change.
_________________________________________________________________
10 Likewise, adjust the birth or death rate of phytoplankton and record how the
populations of phytoplankton and shrimps change.
_________________________________________________________________
11 Stimulating question:
11.1 In this model, the ocean is made up with 46 X 60 cells. What is the
maximum number of shrimps that can be accommodated? Why?
Conjecture: _______________________________________________________
4
Hong Kong Baptist Univeristy
Department of Education Studies
Computer Modelling and Knowledge Building
_________________________________________________________________
12 Fill up the ocean with shrimps and phytoplankton and click the ‘play’ button
. What have you observed?
Observation:
_________________________________________________________________
13 Remove all the living things and then introduce a small number of phytoplankton
and shrimps and press the ‘play’ button. What have you observed?
Observation:
_________________________________________________________________
14 Try a different numbers of phytoplankton and shrimps and repeat (13).
Observation:
_________________________________________________________________
15 What conclusion can be drawn?
Conclusion: _______________________________________________________
________________________________________________________
Task 2：Introduce tuner fish to the marine ecosystem.
16 Tuner fish feed on shrimps. Draw a broken-line graph to illustrate how the
introduction of tuner fish affects the population of shrimps and phytoplankton.
Discuss.
5
Hong Kong Baptist Univeristy
Department of Education Studies
Computer Modelling and Knowledge Building
quantity
shrimp
phytoplankton
tuner
time
17 From http://ited.hkbu.edu.hk/wm/index-dd-2011.html/, download and save
task(eng).wrld on your desktop.
18 Open task(eng).wrld:
and add tuner fish to the
ecosystem. Record how the populations of shrimp, phytoplankton and tuner vary
with time.
Observation:
quantity
shrimp
phytoplankton
tuner
time
19 Question：
If a very large number of tuner fish are introduced to the ecosystem, what will
happen to the populations of shrimps and tuner fish?
Conjecture: _______________________________________________________
6
Hong Kong Baptist Univeristy
Department of Education Studies
Computer Modelling and Knowledge Building
20 Try to introduce a large number of tuner and observe what happens to the
population of shrimps and tuner fish.
Observation：_____________________________________________________
Does the observation align with your conjecture? Why?
_________________________________________________________________
_________________________________________________________________
Task 3：Introduce lancet fish to the ecosystem
21 Both lancet and tuner feed on shrimps. They are competitors in the ecosystem.
Question:
How does the introduction of lancet fish to the ecosystem affect the population of
tuner fish? Run task(eng).wrld and try to find out the answer.
Task 4：Introduce shark to the ecosystem
22 What happen if a large number of shark fish are introduced to the ecosystem?
Run task(eng).wrld and find out the answer on your own.
phytoplankton
shrimp
Figure 2: Variation in the populations of phytoplankton and shrimps.
7