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Ch. 46 - Chemical Signals in Animals
Freeman - Biological Science 7th Edition
Freeman7th EditionBiological ScienceISBN: 9783584863285Not the one you use?Change textbook
All textbooksFreeman 7th EditionCh. 46 - Chemical Signals in AnimalsProblem 14
Chapter 46, Problem 14

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Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world’s largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins’ ability to respond to stressors? Has it affected the penguins’ secretion of corticosterone?
Scientists tested the hypothesis that penguins habituated to tourists have a blunted stress response overall. They examined the corticosterone response of habituated and non-habituated penguins to another stressor—that of being captured and restrained for 30 minutes. They found that both habituated and non-habituated penguins secreted corticosterone in response to being captured and restrained, but that the level of corticosterone after 30 minutes differed between the groups. The results are shown here (* means P<0.05). Was the hypothesis supported? Explain.

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1
Examine the graph provided, which shows the plasma corticosterone levels in Magellanic penguins over time, comparing habituated and non-habituated groups.
Identify the key variables: the x-axis represents time in minutes, and the y-axis represents plasma corticosterone levels in ng/mL. The graph compares two groups: habituated (blue) and non-habituated (red) penguins.
Observe the trend: both groups show an increase in corticosterone levels over the 30-minute period. However, the non-habituated penguins exhibit a higher increase in corticosterone levels compared to the habituated penguins.
Note the statistical significance indicated by the asterisk (*), which suggests that the difference in corticosterone levels between the two groups at 30 minutes is statistically significant (P<0.05).
Interpret the results: The hypothesis that habituated penguins have a blunted stress response is supported by the data, as the habituated penguins show a lower corticosterone response compared to non-habituated penguins when exposed to the stressor of being captured and restrained.

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Key Concepts

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

Habituation

Habituation is a form of learning in which an organism decreases or ceases its responses to a stimulus after repeated exposure. In the context of the Magellanic penguins, habituation refers to their reduced stress response to the presence of tourists, which can lead to changes in their behavior and physiological responses to stressors.
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Corticosterone

Corticosterone is a steroid hormone produced by the adrenal cortex in response to stress. It plays a crucial role in the stress response by regulating energy, immune reactions, and behavior. The study examines how habituation affects the secretion levels of corticosterone in penguins when subjected to stressors like capture and restraint.

Stress Response

The stress response is the body's physiological reaction to perceived threats or challenges, often referred to as the 'fight or flight' response. In this study, the stress response is measured by the levels of corticosterone in penguins, comparing those that are habituated to tourists versus those that are not, to determine if habituation alters their ability to cope with stress.
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Textbook Question

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Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world’s largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins’ ability to respond to stressors? Has it affected the penguins’ secretion of corticosterone?

Corticosterone is a(n):

a. Neurohormone

b. Steroid hormone

c. Amino-acid-derived hormone

d. Polypeptide hormone

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Textbook Question

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Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world’s largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins’ ability to respond to stressors? Has it affected the penguins’ secretion of corticosterone?

In what part(s) of a target cell would you expect to find corticosterone receptors?

631
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Textbook Question

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Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world’s largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins’ ability to respond to stressors? Has it affected the penguins’ secretion of corticosterone?

If penguins in a colony are habituated to the presence of tourists, how would their corticosterone response to being visited by tourists compare to that of penguins in a colony not previously exposed to tourists?

810
views
Textbook Question

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Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world’s largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins’ ability to respond to stressors? Has it affected the penguins’ secretion of corticosterone?

In response to a visit by tourists, which penguins—habituated or non-habituated—would show a greater change in expression of genes for liver enzymes involved in converting amino acids to glucose? Explain.

731
views
Textbook Question

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Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world’s largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins’ ability to respond to stressors? Has it affected the penguins’ secretion of corticosterone?

Suggest at least two distinct physiological mechanisms that could be responsible for the difference in corticosterone response to a stressor in habituated and non-habituated penguins.

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