Chapter 33 - 33 Osmoregulation and Excretion CHAPTER...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Barracuda Coral reef fishes Do Coral Reef Animals Regulate? M ost of us don’t ever think about whether the beautiful animals in a coral reef are osmoregulating—that is regu- lating the quantity of ions, such as Na + , K + , Ca 2+ , Mg 2+ , or Cl , in their body fluids. Some invertebrates (sea anemones and sea stars, for example) do not osmoregulate. Their body fluids con- form to the sea water around them, and they take what they get. Think of the energy they save. They’re not pumping salt here and there to get their osmolarity just right. Remember osmosis? If a cell is in an isotonic solution and the concentra- tion of salts is the same inside and out, there is no net move- ment of water. A cell in a hypotonic solution gains water, and a cell in a hypertonic solution loses water (see Fig. 5.10C). Inver- tebrate animals that live in the sea are isotonic to sea water. They have a lot of salts in their cells, but that is okay because their enzymes are adapted to this osmolarity. Representatives from only a handful of the approximately 34 animal phyla have managed to colonize land. What’s the problem? We know that an appropriate respiratory organ is needed for living on land—gills won’t do, but lungs are great. And we know that legs are much better for locomoting on land than are 33 Osmoregulation and Excretion CHAPTER OUTLINE Metabolic Waste Products Have Diff erent Advantages 33.1 The nitrogenous waste product of animals varies according to the environment 666 33.2 Many invertebrates have organs of excretion 667 The Urinary System Produces and Excretes Urine 33.3 The urinary system includes kidneys that contain tubules 670 33.4 The kidney tubules produce urine 672 The Kidney Is an Organ of Homeostasis 33.5 The kidneys can concentrate urine to maintain water-salt balance 674 33.6 Lungs and kidneys maintain acid-base balance 675 APPLICATIONS HOW LIFE CHANGES Evolution of Vertebrates and the Vertebrate Kidney 668 HOW BIOLOGY IMPACTS OUR LIVES Urinalysis Can Detect Drug Use 673 HOW SCIENCE PROGRESSES Treatment for Urinary Disorders 676 664
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Coral reef Clownfish Cup coral Christmas tree worms fl ippers. But an animal also needs a good osmoregulatory organ, such as the vertebrate kidney. In addition, an animal must have various accessory ways to reduce water loss to the dry air, or it will never make it on land. The blood plasmas of marine vertebrates, such as fishes and sea turtles, are hypotonic to sea water, and when these animals live in a coral reef, they tend to gain salt. The vertebrate kidney is much better at conserving water on land than pumping out extra salts in the marine environment. But the fi shes in the coral reef get a little help from their gills. In marine environments, gills pump salts out; in fresh water, they do the opposite.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern