Question 33·Hard·Command of Evidence
Mean Time (in Seconds) Spent per Flower for Four Pollinator Genera
| Pollinator genus | Seconds per intact pin flower | Seconds per damaged pin flower | Seconds per intact thrum flower | Seconds per damaged thrum flower |
|---|---|---|---|---|
| Habropoda | 2.7 | 5.4 | 4.1 | 9.5 |
| Osmia | 5.2 | 8.2 | 7.1 | 8.3 |
| Pierid | 2.6 | 4.0 | 2.4 | 1.9 |
| Xylocopa | 2.3 | 2.8 | 2.5 | 2.2 |
To study how floral damage affects the behavior of pollinators, such as bees, a team of researchers punched holes in the floral tissue of flowers from the vine yellow jessamine (Gelsemium sempervirens), a plant that produces flowers that have either a long pistil and a short stamen (pin morphs) or a short pistil and a long stamen (thrum morphs). The researchers then compared the time different insect pollinators spent visiting intact pin and thrum flowers to the time such pollinators spent visiting the artificially damaged pin and thrum flowers. The researchers concluded that the effect of floral damage on time spent per flower varied by both floral morph and the genus of the pollinator.
Which choice best describes data from the table that support the researchers’ conclusion?
For “data support” questions, first restate the conclusion in your own words and identify exactly what relationships it claims (here: the effect of damage, across pin vs. thrum flowers, for different genera). Then scan the table systematically: compare intact vs. damaged values for each category (each genus and morph) and note whether the time increases or decreases. Finally, pick the answer that accurately summarizes this overall pattern without introducing errors or focusing on just one number; quickly eliminate any option that contradicts a single data point or fails to involve all the variables mentioned in the conclusion.
Hints
Focus on what needs to be supported
Underline the key parts of the conclusion: it’s about how damage affects time spent, and that this effect varies by both floral morph (pin vs. thrum) and pollinator genus. Any supporting statement must deal with all of these pieces.
Compare intact vs. damaged within each category
For each genus and each flower type (pin and thrum), compare the intact and damaged times. Ask: does damage make them spend more or less time on that type of flower?
Look for a choice that summarizes the full pattern
Once you see the pattern for pin and thrum flowers across all four genera, look for the answer choice that summarizes that pattern across both morphs and multiple genera, not just a single number or a single comparison.
Watch for statements that misread the table
Check the numbers carefully: some choices describe changes (shorter vs. longer time) that don’t match the actual data for one or more genera. Eliminate any option that contradicts even one entry in the table.
Step-by-step Explanation
Understand what the conclusion is claiming
The researchers concluded that the effect of floral damage on time spent per flower varies by both floral morph and pollinator genus. So the supporting data must:
- Compare intact vs. damaged flowers (the effect of damage),
- Distinguish between pin vs. thrum flowers (floral morph), and
- Show differences across genera (Habropoda, Osmia, Pierid, Xylocopa).
Compare intact vs. damaged for pin flowers
Look at the two pin columns for each genus:
- Habropoda: intact pin 2.7, damaged pin 5.4 → time increases with damage.
- Osmia: intact pin 5.2, damaged pin 8.2 → time increases.
- Pierid: intact pin 2.6, damaged pin 4.0 → time increases.
- Xylocopa: intact pin 2.3, damaged pin 2.8 → time increases.
For pin flowers, damage leads to longer times per flower for all four genera.
Compare intact vs. damaged for thrum flowers
Now look at the two thrum columns for each genus:
- Habropoda: intact thrum 4.1, damaged thrum 9.5 → time increases.
- Osmia: intact thrum 7.1, damaged thrum 8.3 → time increases.
- Pierid: intact thrum 2.4, damaged thrum 1.9 → time decreases.
- Xylocopa: intact thrum 2.5, damaged thrum 2.2 → time decreases.
So for thrum flowers, damage leads to longer times only in Habropoda and Osmia, and shorter times in Pierid and Xylocopa. This shows that the effect of damage varies by both flower type and genus.
Match the patterns to the answer choices
Now check which choice correctly describes the patterns you just found:
- A focuses only on pin flowers and compares two genera; it does not address thrum flowers, so it cannot fully support the conclusion (which requires variation by morph and genus).
- B focuses only on thrum flowers and leaves out Osmia; it also doesn’t show the full cross-morph pattern.
- C accurately describes Habropoda, but it uses only one genus, so it doesn’t support the claim that the effect varies by pollinator genus.
- D correctly states that damage increased time per pin flower in all genera and increased time per thrum flower only in Habropoda and Osmia, which directly supports the conclusion.
Therefore, the best choice is D.