Graphing SKills Answer key - YouTube - Free Printable

The image shows a biology lab activity involving the breathing rate of a freshwater sunfish at different water temperatures. The task involves plotting data from a table onto a graph and analyzing the relationship between temperature and breathing rate.

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🔹 Step 1: Understand the Data

Here is the data provided in the table:

| Temperature (°C) | Breathing Rate (per minute) |
|------------------|-------------------------------|
| 10 | 15 |
| 15 | 25 |
| 18 | 30 |
| 20 | 38 |
| 23 | 60 |
| 25 | 57 |
| 27 | 25 |

Note: There are handwritten annotations:
- "low" next to 15°C → possibly indicating low breathing rate.
- "high" next to 23°C → peak breathing rate.
- "high" next to 27°C → but breathing rate drops to 25, so this might be a mistake or mislabeling.

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🔹 Step 2: Plot the Points on the Graph

The graph has:
- X-axis: Temperature (°C), ranging from 0 to 27
- Y-axis: Breathing Rate (per minute), ranging from 0 to 60

You need to plot each (Temperature, Breathing Rate) pair as a point.

Let’s go through them:

1. (10, 15)
2. (15, 25)
3. (18, 30)
4. (20, 38)
5. (23, 60)
6. (25, 57)
7. (27, 25)

> ✔ These points should be plotted on the grid.

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🔹 Step 3: Draw a Trend Line (Best Fit Curve)

After plotting the points:
- You’ll notice that breathing rate increases with temperature up to 23°C (peak at 60 breaths/min).
- Then it decreases slightly at 25°C (57), and sharply drops at 27°C (25).

This suggests:
- An optimal temperature around 23°C for breathing rate.
- Beyond this, the rate declines — possibly due to stress or reduced oxygen solubility in warmer water.

So, the trend is not linear — it's curved, peaking at 23°C.

👉 You should draw a smooth curve that goes up to 23°C and then comes down.

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🔹 Step 4: Interpret the Results

#### 📌 Key Observations:
- As temperature increases from 10°C to 23°C, the breathing rate increases.
- This is likely because metabolic rate increases with temperature.
- At 23°C, the breathing rate is highest (60 breaths/min) — this may be the optimal temperature for the fish.
- From 23°C to 27°C, breathing rate decreases.
- Possible reasons:
- Warmer water holds less dissolved oxygen → fish can't get enough O₂.
- Stress or physiological limits reached.
- Oxygen demand may not be met despite higher metabolism.

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🔹 Conclusion

✔ Answer to the Task:
Plot all seven data points on the graph. Then draw a smooth curve connecting them, showing an increase up to 23°C and a decrease afterward.

➡️ The breathing rate of the freshwater sunfish increases with temperature up to 23°C, after which it decreases. This indicates that 23°C is the optimal temperature for respiration in this species.

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🔍 Additional Notes:

- The drop at 27°C is significant — even though temperature is still rising, breathing rate falls. This could reflect thermal stress or oxygen limitation.
- Always label axes clearly and include units.
- If asked, you might estimate breathing rate at other temps using interpolation.

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Let me know if you'd like help drawing the graph digitally or interpreting further!