When you live and teach in southwest Florida, wetlands are never very far away. My students regularly pass canals, marshes, and seasonally flooded landscapes without necessarily thinking about why those environments look different or how scientists distinguish one wetland from another.

When I introduce wetlands in environmental science classes, students often begin with broad categories based on appearance.

“It’s a swamp,” one student might say.

“How do you know?” I might ask.

“There’s water and trees.”

That answer is not entirely wrong, but it also reveals an opportunity. Students often recognize that an environment is wet without yet understanding the ecological evidence scientists use to classify wetlands. What looks like a simple vocabulary lesson can therefore become an investigation in observation, comparison, evidence, and explanation.

Instead of beginning with a list of wetland definitions for students to memorize, I began structuring the lesson around a different question: What evidence would you need to determine what kind of wetland you are looking at?

Moving Beyond the Label

Wetland classification provides a natural opportunity for scientific sensemaking because students cannot always determine the answer from a photograph alone.

The goal of the lesson is therefore not simply for students to memorize that marshes contain herbaceous vegetation and swamps contain woody vegetation. Instead, students use several forms of evidence to determine which classification is most defensible.

I typically focus on several wetland types that students may encounter in Florida:

• freshwater marshes
• forested swamps
• salt marshes
• mangrove wetlands

Students first receive photographs of several wetland environments without labels. I ask them to record what they notice before they attempt to classify anything. Their observations might include shallow standing water, grasses, tree cover, exposed soil, tidal channels, floating vegetation, or dense roots.

At this stage, I deliberately avoid confirming whether their classifications are correct. Instead, I ask questions such as these:

• What evidence are you using?
• What else would you need to know?
• Could another wetland type look similar?

Those questions move students away from guessing and toward scientific reasoning.

Giving Students More Evidence

After students make an initial classification, I gradually provide additional information about each site. Depending on the example, students may receive details about the following:

• dominant vegetation
• water depth
• duration of flooding
• soil characteristics
• salinity
• geographic location
• seasonal patterns
• organisms commonly found at the site

Students then compare those characteristics with a wetland identification guide. For example, one site might include mostly grasses and sedges, shallow freshwater, hydric soils, and long periods of inundation. Another might contain cypress trees, standing freshwater, saturated soils, and a closed or partially closed canopy. A third site might experience tidal flooding and have salt-tolerant vegetation. Students use the evidence to decide which wetland classification is most consistent with the conditions.

A simple comparison chart helps organize their thinking.

Comparison Chart

A student who writes “freshwater marsh” without explanation may have guessed correctly. A student who explains that the site is dominated by herbaceous vegetation, experiences prolonged shallow flooding, and lacks the woody vegetation characteristic of a swamp is demonstrating something different: using ecological evidence to construct an explanation.

Letting Students Change Their Minds

One of the most useful parts of the activity occurs when students revisit their first answer. I ask them to record answers to these prompts:

• My initial classification was ________.
• My final classification is ________.
• The evidence that caused me to keep or change my answer was ________.

Students sometimes think changing an answer is evidence that they were wrong. I want them to see revision differently: Changing a claim because new evidence becomes available is part of scientific reasoning.

For example, a student may initially classify a site as a marsh because it contains standing water and grasses. After examining hydroperiod data, vegetation, and seasonal conditions, the student may determine that wet prairie is a better classification.

The important question becomes not “Did you get it right the first time?” but “Can you explain why your final claim is better supported?” That shift changes the classroom conversation.

Instead of asking me whether an answer is correct, students begin asking questions such as “Does the flooding have to be permanent?” or “Would these trees make it a swamp even if the water is shallow?” These questions show that students are beginning to reason about the system rather than merely matching vocabulary terms.

Connecting Classification to Function

Once students can distinguish among wetland types, I extend the activity beyond classification.

Students consider how differences in hydrology, soils, salinity, and vegetation influence what each wetland does. This creates an opportunity for them to ask a larger question: If two ecosystems are both wetlands, why might they respond differently to the same environmental change? Students can then consider scenarios involving altered water flow, drought, sea-level rise, nutrient input, development, or invasive species.

For instance, a mangrove wetland experiencing changes in salinity will not respond in exactly the same way as a freshwater marsh. A forested swamp may depend on a different flooding regime than a wet prairie. Classification therefore becomes the beginning of the investigation rather than the endpoint.

Using Local Environments as Evidence

Southwest Florida makes this lesson particularly meaningful because students do not have to imagine wetlands as distant ecosystems—wetlands exist throughout the region. Even when a field trip is not possible, photographs, maps, aerial imagery, and publicly available environmental data can bring local wetlands into the classroom.

This place-based approach has been valuable in my previous science teaching as well. When students investigate organisms and environmental conditions that exist around them, scientific concepts become less abstract. Wetland classification extends that same philosophy while asking students to work with an entirely different kind of ecological evidence.

Shifting from Classification to Sensemaking

The lesson can conclude with an unfamiliar wetland scenario. Students receive a photograph and a short data set containing vegetation, hydroperiod, salinity, soil, and location information. Their task is to answer this question: What type of wetland is this, and what evidence supports your classification? I require students to identify at least three pieces of evidence and explain how those observations support their conclusion.

For an additional challenge, students must identify another plausible classification and explain why the evidence does not support it as strongly. This final step is important because scientists do not simply gather evidence supporting one explanation; they also consider competing explanations and determine which interpretation best fits the available evidence.

Wetland classification therefore becomes a vehicle for several scientific practices at once: observing patterns, analyzing data, constructing explanations, evaluating competing claims, and communicating reasoning.

Seeing Wetlands Differently

One of my goals in environmental science is for students to leave the classroom noticing things they previously passed without considering. A wetland should eventually become more than “a place with water.” Students can begin noticing vegetation, water levels, soil conditions, landscape position, and ecological relationships. The same landscape that once looked like “just a swamp” becomes a system that can be examined and interpreted.

That is where I see the value of sensemaking in science instruction. Once students learn to ask, “What evidence would tell me what I am looking at?” they are practicing a way of thinking that extends far beyond wetlands.
 

Christopher Morales is a high school science teacher in southwest Florida and an adjunct biology instructor. His writing focuses on science education, place-based learning, cognitive load, classroom attention, and instructional design. He teaches environmental science, anatomy and physiology, genetics, and biology across secondary and college settings. LinkedIn: https://www.linkedin.com/in/christopher-morales-ms-18a09418a/

The mission of NSTA is to transform science education to benefit all through professional learning, partnerships, and advocacy.