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A group of scientists did a study to determine the effect of exposure time on the mass of two mollusc species found on a rocky shore - NSC Marine Sciences - Question 2 - 2021 - Paper 1
Question 2
A group of scientists did a study to determine the effect of exposure time on the mass of two mollusc species found on a rocky shore. The scientists used the follow... show full transcript
Worked Solution & Example Answer:A group of scientists did a study to determine the effect of exposure time on the mass of two mollusc species found on a rocky shore - NSC Marine Sciences - Question 2 - 2021 - Paper 1
Step 1
Step 2
2.1.2 Give a suitable hypothesis for this investigation.
Answer
The hypothesis could be: 'The longer the exposure time, the greater the average percentage change in mass for both species'. Alternatively, one might posit that 'The shorter the exposure time, the lower the average percentage change in mass for both species.'
Step 3
2.1.3 Draw a bar graph to illustrate the data for both species as provided in the table above.
Answer
To draw the bar graph:
- Title: 'Average Percentage Weight Loss of Mollusc Species vs Exposure Time'
- X-Axis: 'Exposure Time (Hours)'
- Y-Axis: 'Average Percentage Change in Mass (%)'
- Plot two sets of bars for Species A and Species B, using different colors for each species.
- Ensure to label the axes, including the units, and provide a key for the bars.
Step 4
2.1.4 Using the data provided, identify the species that would likely be found in the:
Answer
(a) Middle eulittoral zone: Species B is likely to be found here because it experienced a lower average percentage change in mass, suggesting it is more suited to this zone. (b) Lower eulittoral zone: Species A is likely to be found here as it tolerated longer exposure times leading to a greater change in mass.
Step 5
2.1.5 Explain your answers to QUESTION 2.1.4(a) and (b) above.
Answer
Species B, with lower percentage change in mass over time, indicates that it is more resilient to exposure and thus can thrive in the more consistently moist middle eulittoral zone. On the other hand, Species A, which shows a greater change in mass, suggests that it is more affected by desiccation and would be better suited to the lower eulittoral zone where conditions are more favorable for retention of moisture.