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The crown-of-thorns starfish (COTS) is one of the main causes of the decline of the world's coral reefs - AQA - A-Level Biology - Question 5 - 2019 - Paper 3
Question 5
The crown-of-thorns starfish (COTS) is one of the main causes of the decline of the world's coral reefs. Marine biologists used a choice chamber to investigate the ... show full transcript
Worked Solution & Example Answer:The crown-of-thorns starfish (COTS) is one of the main causes of the decline of the world's coral reefs - AQA - A-Level Biology - Question 5 - 2019 - Paper 3
Step 1
Step 2
Step 3
Evaluate the journalist's suggestion.
Answer
The journalist suggests that either type of light could affect COTS's movement away from coral reefs. The data presented in Table 1 indicates that the P value for constant light is 0.02, which is statistically significant at typical alpha levels (0.05), suggesting a strong likelihood that COTS do indeed respond more strongly to constant light. In contrast, the P value for flashing light is 0.69, indicating no significant effect. Therefore, the suggestion lacks support from the data. Overall, the conclusion drawn from the study indicates that it is the constant light that significantly influences COTS behavior, rather than both types of light equally.
Step 4
Calculate the shortest time one COTS would take to move up a coral reef from 66 m under water to 18 m under water.
Answer
To find the distance the COTS travels, calculate:
Distance = 66 m - 18 m = 48 m.
Using the maximum speed of COTS moving towards constant light, which is 259 mm/min:
Convert 48 m to mm: 48 m = 48000 mm.
Time = Distance / Speed = 48000 mm / 259 mm/min ≈ 185.34 min.
Convert minutes to hours: 185.34 min / 60 ≈ 3.09 hours.
Rounding to the nearest hour, the shortest time would be approximately 3 hours.