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Lab 1 Worksheet: Dependent and Independent Variabshowing page 1-5 out of 5

Lab 1 Worksheet:
Dependent and Independent Variables
Student instructions
:
Follow the step-by-step instructions for this exercise found within
the virtual lab and the instructions below and record your answers in the spaces below.
This assignment does not have to be submitted for grading but you will be tested on
the information covered in this lab on the assigned weekly quiz.
Directions
1.
Open the virtual lab titled “Dependent and Independent Variables.”
2.
The screen will display the virtual lab simulation on the right side, and a
“Questions” column on the left side.
3.
Read all information in the Greenhouse Handbook.
To open the handbook, click
on “Greenhouse Handbook” on the shelf above the growth chamber in the lab
simulation.
4.
Read all background information and instructions in the “Questions” column.
5.
If you come upon terms that are unfamiliar to you, please refer to your textbook
for further explanation or search the word here:
http://encarta.msn.com/encnet/features/dictionary/dictionaryhome.aspx
6.
Answer Lab Questions 1-5 below.
7.
Follow the procedure below to complete the lab experiment.
There are four seed
varieties: two transgenic varieties—BT 123 and BT 456—and two non-transgenic
varieties—Golden Crop and Super Harvest. You must gather data for all four
varieties at levels of no infestation, low infestation, and high infestation. You may
need to reset the simulation several times to see and select each of the four
varieties. Record all of your data in Tables 1 and 2 below.
Procedure
1.
Click and drag a seed variety
to each of the two growth
chambers.
2.
You may choose to plant one or two different types of corn. The seeds will be
planted in all three pots and each growth chamber will automatically be labeled.
Click on the reset button to choose from other varieties of corn.
1
3.
Click and drag a level of ECB infestation
to each set of plants
in the growth chambers.
4.
You may choose to have no infestation, a low level of infestation,
or a
high level
of infestation for each seed type. The selection will be applied
to each plant in the growth chamber and the label will be updated with the
information of the level of the ECB treatment.
5.
Click on the Grow button. You will see an animation of the calendar indicating
the number of days that have passed. At the end of the time period, the chamber
doors open and the fully grown plants are evaluated.
6.
Click and drag each ear on each of the plants to a separate weighing dish. The
yield of kernels from each plant is now on a weighing dish.
7.
Drag a weighing dish to the balance to read the weight of the kernels. Record the
weight in Table 1 below. Proceed to weigh the kernel yield from each plant.
8.
Calculate the average kernel yield from each set of three plants that were grown
under identical experimental conditions from the same type of seed.
Calculate the Average Yield for each seed variety at each level of infestation.
To calculate the Average Yield for one seed variety at one level of infestation
use the following formula:
Average Yield = (Pot 1 yield + Pot 2 yield + Pot 3 yield)/3
*Round all average yields to the second (hundredth) decimal place.
9.
Click the reset button to repeat the experiment by changing the variable of the
ECB infestation level and/or seed variety.
10. When all data are recorded in Table 1, calculate the Percent (%) Reduction in
Yield for each seed variety.
To calculate the Percent (%) Reduction in Yield for
one seed variety use the following formula:
Percent (%) Reduction in Yield =
(avg. yield with no infest. – avg. yield with high infest.)/avg. yield with no
infest. X 100
2
*Round all Percent (%) Reduction in Yield values to the second (hundredth)
decimal place.
Record this data in Table 2 below.
11. Answer Lab Questions 6-12 below.
Lab Questions
1.
ECB refers to which of the following?
a.
A genetically engineered plant that is resistant to insect pests
b.
Edible corn byproducts
c.
An insect pest that reduces corn yield
d.
European corn borer
e.
Both c and d
2.
How many days are required for a corn seed to become a mature plant with
maximum weight kernels ready to be harvested?
a.
About 23
b.
About 65
c.
About 140
d.
About 180
3.
“BT Corn” refers to corn that:
a.
Has been infested with insect pests
b.
Has been infected with bacteria
c.
Is resistant to ECB
d.
Is not affected by pesticides
4.
What is BT?
a.
A stomach poison produced by bacteria.
b.
A genetically engineered corn product.
c.
A bacterium carried by the European corn borer.
d.
A bacterium that has a gene for producing Cry proteins.
5.
Creation of BT corn requires genetic material from all of the following except:
a.
European corn borer
b.
Bacillus thuringiensis
c.
a corn plant
d.
all of the above contribute genetic material to the production of BT corn
Table 1:
Average Yield (g) for each seed variety at no, low, and high infestation
levels
Seed Variety
Level of
ECB
Pot 1
Yield
Pot 2
Yield
Pot 3
Yield
Average
Yield
3
Infestation
BT 123
None
160.1
164.8
164.2
163.0
Low
164.0
162.6
168.3
164.9
High
155.1
163.0
163.9
160.6
BT 456
None
190.0
183.2
184.8
186.0
Low
178.8
172.6
179.6
177.0
High
157.3
157.0
159.0
157.7
Golden
None
181.6
182.8
189.8
184.7
Low
177.9
171.2
170.6
173.2
High
135.4
139.6
138.3
137.7
Super Harvest
None
164.1
164.3
161.9
163.4
Low
159.1
155.0
157.5
157.2
High
125.5
129.0
130.0
128.1
Table 2:
% Reduction in yield for each seed variety at high levels of infestation
(Transfer data on Average Yield (g) with No Infestation and High Infestation from Table
1 to Table 2)
Seed Variety
Avg. Yield with
No Infestation
Avg. Yield with
High Infestation
% Reduction
in Yield
BT 123
163.0
160.6
.01
BT 456
186.0
157.7
1.00
Golden
184.7
137.7
1.00
Super Harvest
163.4
128.1
1.00
6.
For each seed variety, why did you need to collect data from 3 pots for each
infestation level to obtain reliable data?
4
7.
Which seed variety has the highest yield under conditions of no infestation?
8.
Which transgenic seed variety was most resistant to the ECB at high infestation
levels?
9.
Which non-transgenic seed variety was most resistant to the ECB at high
infestation levels?
10. Compare the yield of Super Harvest seeds and BT 123 seeds under conditions of
no infestation. Is there any significant difference in the average yield?
11. If you compared one pot of Super Harvest and one pot of BT 123 with no
infestation, would you expect the yield of each pot to be within 0.5g of the other?
Explain your answer.
12. A farmer decides to plant 90% of one field with BT 123 seeds and the remaining
10% of the field with a different seed variety. He hopes this will slow the
evolutionary development of BT resistant insects. Which seed variety should he
use to plant the 10% of his field that is not planted with BT 123 seeds? Explain
your answer.
5