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Daphnia (Daphnia pulex) is a species of water flea that lives in fresh water - Scottish Highers Biology - Question 2 - 2018
Question 2
Daphnia (Daphnia pulex) is a species of water flea that lives in fresh water. An investigation was carried out into the effect of water temperature on the heart rate... show full transcript
Worked Solution & Example Answer:Daphnia (Daphnia pulex) is a species of water flea that lives in fresh water - Scottish Highers Biology - Question 2 - 2018
Step 1
Calculate the average increase in heart rate per °C between 2°C and 22°C.
Answer
To calculate the average increase in heart rate per °C, we first find the difference in heart rate between 2°C and 22°C:
Heart rate at 22°C = 219 bpm
Heart rate at 2°C = 175 bpm
Difference = 219 - 175 = 44 bpm
Now, we determine the temperature difference:
Temperature difference = 22°C - 2°C = 20°C
Finally, we calculate the average increase in heart rate per °C:
Average increase = ( \frac{44 \text{ bpm}}{20 \text{ °C}} = 2.2 \text{ bpm per °C} )
Step 2
Daphnia is a conformer. Use evidence from the table to confirm this statement.
Answer
Daphnia is a conformer because its heart rate increases with the increase in water temperature. As seen in the table, from 2°C to 22°C, both the water temperature and heart rate increase together, indicating that Daphnia's physiological processes are directly affected by the external temperature.
Step 3
Explain how an increased water temperature would result in a higher metabolic rate in Daphnia.
Answer
Increased water temperature leads to an increase in enzyme activity as many enzymes have optimal functioning at higher temperatures. This increase in enzyme activity results in enhanced respiration and ATP production. Additionally, a higher temperature promotes increased diffusion rates, facilitating a greater supply of oxygen and nutrients to the Daphnia, which supports higher metabolic processes.
Step 4