Virtual Lab: Dependent and Independent Variables
Worksheet

1. ECB refers to: 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. 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? e. about 23 f. 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. BT is: 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 for each seed variety at no, low, and high infestation levels

Seed Variety | Level of ECB Infestation | Pot 1 Yield | Pot 2Yield | Pot 3Yield | Average Yield | BT 123 | None | 160.1 | 164.8 | 164.2 | 163 | | Low | 164.0 | 162.6 | 168.3 | 165 | | High | 157.3 | 157 | 159 | 156.8 | BT 456 | None | 190 | 183.2 | 184.8 | 186 | | Low | 178.8 | 172.6 | 179.6 | 177 | | High | 157.3 | 157 | 159 | 157.8 | Golden | None | 181.6 | 182.8 | 189.8 | 184.7 | | Low | 159.1 | 155 | 157.2 | 157.2 | | High | 135.4 | 139.6 | 138.3 | 136.8 | Super Harvest | None | 164.1 | 164.3 | 161.9 | 163.4 | | Low | 159.1 | 155 | 157.5 | 157.2 | | High | 125.5 | 129 | 130 | 128.2 |

Table 2: % Reduction in yield for each seed variety at high levels of infestation
(transfer data on average yield 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 | 156.8 | 96 | BT 456 | 186 | 157.8 | 85 | Golden | 184.7 | 136.8 | 74 | Super Harvest | 163.4 | 128.2 | 78 |

6. For each seed variety, why did you need to collect data from 3 pots for each infestation level to obtain reliable data? So, you could see how different things would affect the plant. You need to be able to see results from multiple experiments in order to get accurate data.

7. Which seed variety has the highest yield under conditions of no infestation? BT 456

8. Which transgenic seed variety was most resistant to the ECB at high infestation levels? BT 456 9. Which non-transgenic seed variety was most resistant to the ECB at high infestation levels? Golden

10. Compare the yield of Super Harvest seeds and BT 123 seeds under conditions of no infestation. Is there any difference in the avg. yield? The yields are the same for both seed varieties

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? Explain your answer. Yes, because these seed varieties are similar in type. They would have the same outcome if there were no infestations.

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 the 10% of his field that is not planted with BT 123 seeds? Explain your answer. He should plant Super harvest, because it has the same qualities as the BT 123. Also, it does have a lower yield rate during the high infestation. This would help balance out during that period.