Module 4: Viva la Difference!

High School Level


Florida’s freshwater lakes, rivers and ponds are different from those found up north and other regions of the country. Many of our waterbodies have an abundance of large plants (macrophytes) or microscopic plants (algae). Often they have both. This has a lot to do with naturally occurring nutrients in our soils and the fact that most of our lakes tend to be shallow with warm water temperatures throughout most of the year. Module 4 draws on these unique characteristics as part of an introduction to the Trophic State Classification System, beginning with the 20-minute presentation, Viva la Difference! Students will come away with an understanding of how the trophic state classification system enhances our ability to assess the biological productivity of a waterbody; how it can help us determine if a waterbody is changing; and how it can help us do a better job of managing our freshwater resources for all user groups, including wildlife.

This module builds on the key concepts of native, non-native and invasive plants discussed in Module 1 (see Silent Invaders) and explains how invasive plants influence trophic state. It may also be used as a stand-alone activity or supplement to other curricula about trophic state and eutrophication. Lessons and activities are designed to further reinforce the Big Ideas of Science and Society, Interdependence, Diversity and Evolution of living organisms.


  • Define the trophic state classification system and identify the differences between eu-, meso-, oligo-, hypereu- trophic states
  • Identify the characteristics measured to determine trophic state
  • Understand the influence invasive plants have on Florida freshwater ecosystems
  • Learn how science can help us make informed decisions

Lesson Plans & Activities

Introductory Materials
Lessons & Activities