Lesson 2: Oyster Biology

Overview

Students develop a basic understanding of oyster biology with a focus on their ability to filter water which helps combat water pollution and eutrophication.

Standards

SEV1. Obtain, evaluate, and communicate information to investigate the flow of energy and cycling of matter within an ecosystem. c. Analyze and interpret data to construct an argument of the necessity of biogeochemical cycles (hydrologic, nitrogen, phosphorus, oxygen, and carbon) to support a sustainable ecosystem. e. Plan and carry out an investigation of how chemical and physical properties impact aquatic biomes in Georgia.  SEV4. Obtain, evaluate, and communicate information to analyze human impact on natural resources.  a. Construct and revise a claim based on evidence on the effects of human activities on natural resources.

Engage

The phenomenon of oysters filtering water is the perfect way to engage your students in this lesson. If possible, visit the UGA Marine Extension and have your students participate in the Oysters: The Fantastic Filterers lab so that they can witness this process firsthand.

If that is not an option. Have them watch the video below. You many choose to have students complete an “I see, I think, I wonder…” three-column chart as they watch the video. You can print out the chart, or just have them create their own in their journal. Have students share their observations in small groups and then whole group. One way to ensure that all students participate in the group discussions is to let them know in advance that you will doing a random callout. That way they can make sure to prepare during their small group conversation. This type of discussion is perfect for a random callout because there are no wrong answers.

This video is another good option that compares water with oysters to water without oysters, so it gives the students a bit more to think about.

Explore

The ideal way for students to explore this concept is to complete an oyster dissection and plankton observation so that they can see how the oysters filter the water, and view their food, phytoplankton, under a microscope. This is all done as part of the Oysters: The Fantastic Filterers lab, however, if you are not able to attend the lab you can do an oyster dissection in your classroom, and the video below will help you guide your students through this process.

Oysters can be harvested from a recreational reef, or purchased from your local seafood market. As students explore the oysters anatomy have them record their observations with words, numbers and pictures in their journal. Have them start with the external parts, reminding students to record qualitative observation using their senses, and quantitative observations as well. If possible, provide rulers and scales. Ask students to create a detailed sketch that includes color. Next, shuck the oyster and have them explore the internal anatomy. If you can collect a water sample (preferably with a plankton tow net) your students will be able to create wet mounts and view the plankton under the microscope.

Explain

Explain to students how the internal anatomy they viewed helps the oyster to filter the water. Show them how oysters are able to digest the food they need, and spit out what they don’t. Feel free to use the slideshow below to guide this discussion.

Google Slides- Lesson 2- Explain (make a copy to edit)

*If your students have participated in the lab at UGA MAREX, they will have had this information explained to them already, but you may choose to review the slideshow in your classroom.

Elaborate

In the Explain portion of the lesson students learned that oysters help control some of the physical (turbidity) and chemical properties (nitrogen and phosphorous) that may impact the health of the estuary. In this lesson, students will learn how and why scientists monitor those properties. Feel free to use this presentation that was created for Georgia’s Adopt-a-Wetland program (a citizen science program used to collect water quality data) to share the water quality parameters that scientists and citizen scientists use to check the health of a body of water.

Give students time to test out the equipment (depending on the tools and test kits you have available) and collect water quality data on a sample you have provided from a local body of water. Students can use the Water Quality Testing Playlist to help them learn how to use the equipment. Select the videos for the equipment you have on hand. You may have other types of equipment such as probes, or pH strips and will have to show student how to use the equipment. For longer tests, such as the dissolved oxygen or nitrates tests, being able to watch, pause and rewind a “how to” video can be very useful. Have students record try as many different tests as time allows and record their data in their journals.

At the end of the activity, ask students what they think might happen to an ecosystem if these measurements fall outside of the normal range for a particular ecosystem? For example, if the pH were too low what might happen to the oysters? What happens if the nitrate levels are too high?

Evaluate

In this portion of the lesson, students will work in groups or partners to design their own investigation to determine how one particular physical or chemical characteristic can affect an aquatic biome. Depending on your location, students may be able to conduct their investigations in the field over an extended time. For example, they could collect data to determine how water temperature affects dissolved oxygen. Or, you may choose to have students set up their investigation in the classroom depending on materials and resources available.

If students are having a hard time coming up with a research question, here are a few ideas to get them started:

• How does a change in nitrates levels affect dissolved oxygen?
• How does a change in salinity levels affect pH?
• How does a change in dissolved oxygen affect algae growth?

References

Thank you to Tom Bliss, Luke Roberson and my former students at the Tybee Island Maritime Academy for assisting with the content on this page.