Crows break the shells of certain molluscs before eating them by dropping them onto rocks. Hypothesizing that crows drop the molluscs from a height that gives the most food for the least effort (optimal foraging), a researcher dropped shells from different heights and counted the drops it took to break them. a. The researcher measured the average drop height for crows and found that it was 5.23 m. Does this support the researcher's hypothesis? Explain. b. Describe an experiment to determine whether dropping molluscs from an optimal height is learned or innate.

Verified step by step guidance

1. Step 1: Analyze the data provided in the table. The table shows the height of drop (m), the average number of drops required to break the shell, and the total flight height (calculated as the number of drops multiplied by the height per drop). The goal is to determine if the average drop height of 5.23 m aligns with the hypothesis of optimal foraging.
2. Step 2: Compare the total flight height values in the table. Optimal foraging suggests that crows would choose a drop height that minimizes the total effort (total flight height). From the table, the drop height of 5 m has the lowest total flight height (30 m), indicating it requires the least effort to break the shell.
3. Step 3: Evaluate the average drop height of 5.23 m observed in crows. This value is close to the drop height of 5 m, which minimizes effort according to the data. This supports the hypothesis that crows drop molluscs from a height that optimizes foraging efficiency.
4. Step 4: To determine whether dropping molluscs from an optimal height is learned or innate, design an experiment. One approach is to observe juvenile crows that have not been exposed to adult crows. Provide them with molluscs and measure the drop heights they choose over time. Compare their behavior to adult crows to see if they naturally select optimal heights or if they learn this behavior through observation.
5. Step 5: Another experimental approach is to manipulate the environment. For example, raise crows in isolation without exposure to molluscs or other crows, then introduce molluscs and observe their drop height choices. If they consistently choose optimal heights, this suggests the behavior is innate. If their choices improve with experience or exposure to other crows, this suggests the behavior is learned.

Key Concepts

Optimal Foraging Theory

Optimal Foraging Theory posits that animals will maximize their energy intake per unit of foraging time. This means that crows, when dropping molluscs, would ideally choose a height that minimizes the effort required to break the shells while maximizing the food obtained. The researcher's hypothesis suggests that crows have evolved to drop shells from a height that reflects this balance.

Innate vs. Learned Behavior

Innate behaviors are instinctual and do not require learning or experience, while learned behaviors are acquired through interaction with the environment. To determine if crows' dropping behavior is innate or learned, an experiment could involve observing young crows in isolation to see if they drop shells without prior exposure to the behavior, or if they need to observe other crows first.

Experimental Design

Experimental design involves planning how to conduct an experiment to test a hypothesis effectively. In this case, the researcher must control variables such as the type of mollusc and the environment to ensure that the results accurately reflect the relationship between drop height and the number of drops needed to break the shells. This design is crucial for drawing valid conclusions from the data collected.