Heliconia metallica is a plant found in the understory of tropical rain forests

Heliconia metallica is a plant found in the understory of tropical rain forests. (The understory is the area below the forest canopy.) H. metallica flowers are normally pollinated by hummingbirds. The flowers can be self-pollinated (egg and pollen are from the same H. metallica plant) or cross-pollinated (egg and pollen are from different H. metallica plants).

The following study was conducted to investigate the effects of different pollination treatments on fruit production and seed mass in a population of H. metallica.

Study

Before pollination could occur, the anthers (pollen-producing structures) were removed from each of 400 H. metallica flowers. Then, the flowers were covered with nylon bags to prevent the normal pollinators from pollinating the flowers. The covered flowers were divided equally into 4 groups (Groups 1-4), and each group received a different pollination treatment (see Table 1). Four weeks after the pollination treatments, the percent of flowers that produced fruit and the average mass per seed were determined for each group (see Figures 1 and 2, respectively).

7. The data that were averaged to produce the results shown in Figure 2 were most likely collected using which of the following pieces of equipment?

A. Balance
B. pH meter
C. Telescope
D. Thermometer

8. One of the questions about H. metallica plants that the study was designed to answer was which of the following?

F. Does the location of the plants in the understory of tropical rain forests determine whether the flowers are self-pollinated or cross-pollinated?
G. Are the percent of flowers that produce fruit and the average mass per seed different when flowers are self-pollinated than when flowers are crosspollinated?
H. How long after the plants are pollinated does the fruit ripen?
J. Are the flowers normally pollinated by hummingbirds?

9. The pollination treatments received by Groups 1 and 2 differed in which of the following ways? The pollen received by each Group 1 flower was:

A. from the same plant as the flower, whereas the pollen received by each Group 2 flower was from a different plant than the flower.
B. from a different plant than the flower, whereas the pollen received by each Group 2 flower was from the same plant as the flower.
C. collected from 1 plant, whereas the pollen received by each Group 2 flower was collected from 6 plants.
D. collected from 6 plants, whereas the pollen received by each Group 2 flower was collected from 1 plant.

10. For any group, the value shown in Figure 1 was most likely calculated using which of the following expressions?

F. (number of seeds / total seed mass) × 100
G. (total seed mass / number of seeds) × 100
H. (number of flowers producing fruit / total number of flowers) × 100
J. (total number of flowers / number of flowers producing fruit) × 100

11. The anthers were most likely removed from the flowers for the purpose of ensuring that the flowers:

A. would spontaneously self-pollinate.
B. would not spontaneously self-pollinate.
C. would be pollinated by hummingbirds.
D. would not be pollinated by hummingbirds.

12. Do the results of the study indicate that the nylon bags successfully prevented the normal pollinators from pollinating the H. metallica flowers?

F. Yes; only 20% of the flowers receiving the self-pollination treatment produced fruit.
G. Yes; none of the flowers receiving the no pollination treatment produced fruit.
H. No; only 20% of the flowers receiving the selfpollination treatment produced fruit.
J. No; none of the flowers receiving the no pollination treatment produced fruit.

13. What was the total mass of the seeds produced by the Group 3 flowers?

A. 0 mg
B. 45 mg
C. 85 mg
D. Cannot be determined from the given information

Answers

7. The best answer is A. In order to answer this item, the examinee must know that a balance is used to determine mass. Figure 2 gives the average mass per seed for each group. In order to determine the average mass per seed, the scientists would have to measure the mass of the seeds using a balance.

8. The best answer is G. According to the passage, the experiment was conducted to investigate the effects of different pollination treatments on fruit production and seed mass.

9. The best answer is A. According to Table 1, the flowers in Group 1 were self-pollinated whereas the flowers in Group 2 were cross-pollinated, using pollen from a single donor.

10. The best answer is H. Figure 1 shows the percent of flowers that produced fruit. In order to calculate this percentage, the examinee must divide the number of flowers that produced fruit by the total number of flowers.

11. The best answer is B. According to the passage, the anthers are the pollen-producing structures in the flower. By removing the anthers, the flower would not be able to spontaneously self-pollinate.

12. The best answer is G. According to Figure 1, 0% of the flowers in Group 4 produced fruit. This suggests that the nylon bags successfully prevented the normal pollinators from pollinating the flowers, because none of the flowers in Group 4 were pollinated.

13. The best answer is D. The results given indicate the average mass per seed but not the number of seeds. Without knowing the number of seeds, one cannot figure out the total mass of the seeds.