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Ch. 44 - Osmoregulation and Excretion
Campbell - Campbell Biology 12th Edition
Urry12th EditionCampbell BiologyISBN: 9785794169850Not the one you use?Change textbook
All textbooksUrry 12th EditionCh. 44 - Osmoregulation and ExcretionProblem 3
Chapter 44, Problem 3

Which of the following animals generally has the lowest volume of urine production?
a. Vampire bat
b. Salmon in fresh water
c. Marine bony fish
d. Freshwater flatworm

Verified step by step guidance
1
Understand the concept of osmoregulation, which is the process by which animals control the concentration of water and salts in their bodies to maintain homeostasis.
Consider the environment in which each animal lives, as this affects their osmoregulatory strategies. Marine animals often face different challenges compared to freshwater animals.
Marine bony fish live in a saltwater environment, where the concentration of salt is higher outside their bodies than inside. To prevent dehydration, they drink seawater and excrete the excess salts through their gills and produce very little urine.
Freshwater animals, like salmon in fresh water and freshwater flatworms, live in environments where the concentration of water is higher outside their bodies. They tend to excrete large amounts of dilute urine to get rid of excess water.
Vampire bats, which feed on blood, have a diet that influences their water balance differently, but they are not typically associated with minimal urine production compared to marine bony fish.

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Key Concepts

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

Osmoregulation

Osmoregulation is the process by which animals maintain the balance of water and salts in their bodies to ensure proper cellular function. Marine bony fish, for example, live in a high-salinity environment and must excrete excess salts while conserving water, leading to low urine production. Understanding osmoregulation helps explain how different animals adapt to their environments.
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Habitat and Water Availability

The habitat of an animal significantly influences its water conservation strategies. Marine bony fish live in saltwater, where water is scarce due to high salinity, necessitating adaptations to minimize water loss. In contrast, freshwater animals like salmon and flatworms have abundant water, affecting their urine production differently.
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Excretory System Adaptations

Animals have evolved various excretory system adaptations to manage water and salt balance. Marine bony fish possess specialized kidneys and gills that help excrete salt and conserve water, resulting in minimal urine output. These adaptations are crucial for survival in their saline environment, contrasting with freshwater species that excrete more dilute urine.
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Related Practice
Textbook Question

Unlike an earthworm's metanephridia, a mammalian nephron

a. Is intimately associated with a capillary network.

b. Functions in both osmoregulation and excretion.

c. Receives filtrate from blood instead of coelomic fluid.

d. Has a transport epithelium.

Textbook Question

Which process in the nephron is least selective?

a. Filtration

b. Reabsorption

c. Active transport

d. Secretion

Textbook Question

The high osmolarity of the renal medulla is maintained by which of the following?

a. Active transport of salt from the upper region of the descending limb.

b. The loose packing of juxtamedullary nephrons.

c. Diffusion of urea into the collecting duct.

d. Diffusion of salt from the descending limb of the loop of Henle.

Textbook Question

In which of the following species should natural selection favor the highest proportion of juxtamedullary nephrons?

a. A river otter

b. A mouse species living in a temperate broadleaf forest

c. A mouse species living in a desert

d. A beaver

Textbook Question

African lungfish, which are often found in small stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?

a. Urea takes less energy to synthesize than ammonia.

b. Small stagnant pools do not provide enough water to dilute ammonia, which is toxic.

c. Urea forms an insoluble precipitate.

d. Urea makes lungfish tissue hypoosmotic to the pool.