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Ch. 33 Control Systems in Plants
Taylor - Campbell Biology: Concepts & Connections 10th Edition
Taylor, Simon, Dickey, Hogan10th EditionCampbell Biology: Concepts & ConnectionsISBN: 9780136538783Not the one you use?Change textbook
All textbooksTaylor, Simon, Dickey, Hogan 10th EditionCh. 33 Control Systems in PlantsProblem 19
Chapter 33, Problem 19

A plant biologist observed a peculiar pattern when a tropical shrub was attacked by caterpillars. After a caterpillar ate a leaf, it would skip over nearby leaves and attack a leaf some distance away. Simply removing a leaf did not trigger the same change nearby. The biologist suspected that a damaged leaf sent out a chemical that signaled other leaves. How could this hypothesis be tested?

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Formulate a clear hypothesis: The biologist hypothesizes that a damaged leaf releases a chemical signal that deters caterpillars from eating nearby leaves.
Design an experiment: Divide the shrub into two groups of leaves. In the experimental group, damage a leaf and collect any chemicals released by it. In the control group, do not damage any leaves.
Apply the chemical: Take the chemical collected from the damaged leaf and apply it to undamaged leaves on a different shrub. Leave other leaves untreated as a control.
Introduce caterpillars: Place caterpillars on the shrub with both treated and untreated leaves. Observe whether the caterpillars avoid the treated leaves and prefer the untreated ones.
Analyze the results: Compare the feeding patterns of the caterpillars on treated versus untreated leaves. If the treated leaves are avoided, it supports the hypothesis that the damaged leaf releases a chemical signal.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Plant Communication

Plants can communicate with each other through various means, including chemical signals. When a leaf is damaged, it can release volatile organic compounds (VOCs) that serve as warning signals to nearby plants, prompting them to activate their defense mechanisms. This phenomenon illustrates how plants can respond to threats in their environment, enhancing their survival.
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Chemical Ecology

Chemical ecology studies the role of chemicals in interactions between organisms and their environment. In the context of the question, the focus is on how plants use chemical signals to communicate distress or damage. Understanding these chemical interactions can help researchers design experiments to test hypotheses about plant responses to herbivory.
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Experimental Design

To test the biologist's hypothesis, a well-structured experimental design is essential. This could involve controlled experiments where damaged leaves are isolated and the responses of nearby leaves are monitored. By manipulating variables and observing outcomes, researchers can determine if the chemical signals from damaged leaves influence the behavior of other leaves in the vicinity.
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