• During the lesson introduction, assess students’ understanding of the concepts of biotic, abiotic, and biome and provide review and reinforcement as needed.
• Assess the general knowledge of the class through the large-group identification during the Lentic and Lotic Ecosystems ID activity and the individual mapping activity.
• Collect students’ Lentic and Lotic Ecosystems worksheet for individual assessment.

If computers with Internet access are available for students, instead of the Lentic and Lotic Ecosystems ID activity, have them do the interactive Lentic Ecosystem or Lotic Ecosystem activity at www.mrsoshouse.com/water/wintro.html. Have them read the introduction, and then click “Click Here to Begin.”

Day 1

Begin the lesson by asking students to think of a local pond or river. Challenge them to list as many biotic and abiotic factors in the pond or river ecosystem as they can in just two minutes. If needed, define biotic and abiotic before beginning the activity. Call on students to share answers from their lists. Clarify any misunderstandings about biotic versus abiotic factors.

On the board, write the words: pond, river, creek, lake, brook, bog, fen, spring, swamp. Have students classify them into two groups, based on their common characteristics. Call on students to share their answers until you find someone with the groups “pond, lake, swamp, bog, fen” and “river, brook, spring, creek.” Define lentic and lotic ecosystems, and tell students that this lesson will focus on identifying them and describing their biotic and abiotic components.

Erase the types of lentic and lotic systems and write “lentic = standing water” and “lotic = flowing water” on the board. It may be helpful to share the following tip: One way to remember the difference is that “lentic” sounds like “lentil soup,” which you can picture standing still in a bowl, just like lentic systems such as ponds are standing water often in a bowl shape.

Tell students that lentic and lotic systems are both categories in the freshwater aquatic biome. If biome is not a familiar concept, define the term as “a region on Earth with similar climate, plants, and animals.” Have students identify other biomes they are familiar with. (Note: Sometimes, lentic ecosystems are differentiated from wetlands, which are areas that are wet or covered with water for at least part of the year, with seasonal variations of water depth, sometimes including dry periods when there is no water at the surface. The four major wetland types are: marsh, swamp, bog, and fen. In this unit, the term lentic is used to include wetlands.)

Pennsylvania Lentic and Lotic Ecosystems ID

Divide the class into five groups and give each group a different set (one page with two photos) of photos of Pennsylvania Lentic and Lotic Ecosystems (S-7-5-1_Lentic and Lotic Photos and KEY.docx). Have the groups look at both photos and read the descriptions below them, and then identify whether each photo depicts a lentic or lotic ecosystem. Have one student from each group present the photos and descriptions, and explain why they identified them as lentic or lotic. Also, have them identify biotic and abiotic factors in each photo. Correct any misconceptions during this activity.

Hand out the Lentic and Lotic Ecosystems Descriptions reading activity (S-7-5-1_Lentic and Lotic Descriptions and KEY.docx). Have students read it individually and then complete Part 1, the T-chart, listing features of lentic and lotic ecosystems and Part 2, identifying biotic and abiotic factors. The T-chart and biotic/abiotic factors can be assigned for homework if time is limited. Review the answers with the class and have students revise their work as needed.

Day 2

Lentic and Lotic Ecosystems

Hand out copies of the Pennsylvania Lakes and Rivers Map (S-7-5-1_Pennsylvania Lakes and Rivers Map.pdf). Have students label the rivers and lakes of Pennsylvania with an “LE” or “LO” to denote whether they are lentic or lotic. Key to map: Lakes are lentic (LE) and rivers are lotic (LO).

Have students complete the Lentic and Lotic Ecosystems worksheet (S-7-5-1_Lentic and Lotic Ecosystems Worksheet and KEY.docx). Review the answers with the class.

To close the lesson, have students identify several lentic and lotic ecosystems in the local area. Have them describe the biotic and abiotic factors that they have observed personally at those locations (e.g., ducks on a lake, reeds in a pond, and fish in a river).

Extension:

• For students who might need an opportunity for additional learning, as they read the Lentic and Lotic Ecosystems Descriptions, have them use highlighters (two colors) to identify the features of lentic and lotic ecosystems, in preparation for completing the T-chart.
• During the Lentic and Lotic Ecosystems ID activity, provide students with extra practice by having them classify and describe additional photos that exemplify each type of ecosystem. For extra practice, have them do the Understanding Lotic and Lentic Water Environments online activity (see Related Resources).
• Challenge students who might be going beyond the standards to build a classroom pond habitat, such as one found at www.kidsgardening.com/growingideas/projects/june04/pg1.html. Over time, they can explain interactions among organisms in the pond based on direct observation.