Experimental Pollination vs. Natural Pollination Results
The experiment provides key data points for comparison:
- Experimental pollination during the day yielded fruit in $40\%$ of flowers.
- Experimental pollination during the night yielded fruit in $80\%$ of flowers.
- Natural pollination during the day yielded fruit in $35\%$ of flowers.
- Natural pollination during the night yielded fruit in $20\%$ of flowers.
Analysis of Night Pollination Effectiveness
The experimental results show that night pollination has a high potential for success, achieving $80\%$ fruit yield when pollination is directly controlled. This indicates that the flowers themselves are capable of successful fertilization at night.
Evaluating Explanations for Low Natural Night Pollination
The natural pollination rate during the night was only $20\%$, significantly lower than the experimental rate of $80\%$. This discrepancy suggests an issue with the natural night pollinators.
- Low Abundance (Option 1): If night pollinators are low in abundance, they would be less effective at pollinating flowers compared to experimental intervention, explaining the $20\%$ rate versus the $80\%$ experimental rate. This is a plausible explanation.
- Low Efficiency (Option 3): If night pollinators are low in pollination efficiency, they might not effectively transfer pollen even if present, leading to a low fruit yield. This is also a plausible explanation for the $20\%$ rate.
- Daytime Pollinator Activity (Option 4): The natural day pollination rate ($35\%$) is higher than the natural night rate ($20\%$), and experimental day pollination ($40\%$) is also higher than natural night pollination. This suggests that daytime pollinators are more effective or active naturally. This statement is supported by the data.
- Abundant Night Pollinators (Option 2): If night pollinators were abundant, and we know night pollination is highly effective ($80\%$ experimental), then the natural night pollination rate should ideally be much higher than $20\%$. The low natural rate strongly contradicts the idea of abundant night pollinators. Therefore, this statement is NOT a plausible explanation for the observed results.
Conclusion
The statement that night pollinators are abundant is not a plausible explanation because the experimental data shows night pollination is highly effective, yet natural night pollination yielded significantly fewer fruits.
Important Questions from Community interactions
- Certain species of ibex and weevils depend on the same food source. A study finds that the removal of ibex results in an increase in the number of weevils, but the removal of weevils does not affect the ibex. Which one of the following options best describes this interaction?
- Fungus S infects elm trees and fungus T infects chestnut trees, and both kill their hosts within a year of infection. A forest with equal density of elm and chestnut trees is colonized by both pathogenic fungi. A 100 years later, the elm tree population has declined and the chestnut trees have become extinct. Which one of the following mechanisms would NOT contribute to this outcome?
- Which one of the following is a result of antagonistic coevolution?
- Observations of algal species showed that their diversity was higher in pools where there were grazing snails compared to pools without snails. Which one of the following statements best explains this result?
- Which one of the following ecological processes best explains the observation thatseedling establishment increases with distance from the parent tree in a forest?
