Introduction to Excretion Systems

Explain how different excretion systems function

Microorganisms and invertebrate animals use more primitive and simple mechanisms to get rid of their metabolic wastes than the mammalian system of kidney and urinary function. Three excretory systems evolved in organisms before complex kidneys: vacuoles, flame cells, and Malpighian tubules.

What You’ll Learn to Do

  • Explain how vacuoles, present in microorganisms, work to excrete waste
  • Describe the way in which flame cells and nephridia in worms perform excretory functions and maintain osmotic balance
  • Explain how insects use Malpighian tubules to excrete wastes and maintain osmotic balance
  • Identify common wastes and waste systems

Learning Activities

The learning activities for this section include the following:

  • Comparing Excretion Systems
  • Nitrogenous Wastes
  • Self Check: Excretion Systems