Investigating Macroinvertebrates: How Clean is Our Lake?
Summary
In this outdoor field study, students will collect and identify as many types of macro invertebrates that they find in Lake Bemidji using an identification key. Additionally students will create investigable questions regarding the macro invertebrates and conduct research to answer their questions. Finally, the students will make a general determination as to the cleanliness of Lake Bemidji by using a chart which identifies the sensitivity level of macro invertebrates to pollution.
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Learning Goals
The students will identify the various macro invertebrates that they collect by comparing and contrasting them to the identification key. Next they will sketch and describe each one that is identified and finally, will conclude, based on the types of macro invertebrates collected, the level of pollution in Lake Bemidji.
Context for Use
This field activity is appropriate for grades 4-6 along the edge of a lake or stream. Smaller groups of 10-15 are the ideal size for this activity, although a larger group is manageable, especially if the students are working in groups. Additionally, this activity will take place in at approximately 3 sessions, depending on individual classroom time constraints. The setting of the first session is along the lake where macro invertebrates are obtained and identified; it will take at least an hour. The second and third sessions take place in the classroom where students find answers to questions they have developed, using various print resources.
Description and Teaching Materials
Equipment needed: Scoops, dip nets or kick seines, wading boots or bare feet, dish pans, smaller containers for observing the macro invertebrates (ice cube trays work great), hand lenses and or microscopes.
This lesson needs to begin with a thorough discussion about safety along the water's edge. Once that has occurred, a discussion should ensue with the entire class to discuss what students already know and what they wonder regarding Macro invertebrates. (K-W-L Chart) Next, students are introduced to the Macro invertebrate Identification Keys. (The link is provided below.) Students should work with either a partner or a group and familiarize themselves with the Identification Keys. Then, students wade into the water and begin collecting macro invertebrates. The macro invertebrates are placed in a dishpan that already contains some lake water. Once the students have collected a number of macro invertebrates they can leave the water and move to a site where they are able to work. At the work site the students should isolate individual macro invertebrates, make observations using hand lenses or microscopes, write and sketch their observations in their journals, and use the Identification Keys to identify them, this should also be recorded in their journals.
Once the students have identified their macro invertebrates and all information is recorded in their journals, then the students should create a list of questions that they have and a discussion should take place reviewing all that the students have learned to this point and should also create a list comprised of two or three of each of the groups questions. This is a good ending point for this class session.
The second session begins where the last one ended. Revisit the previous class discussion and the list of questions created. At this point, the lesson can take many different directions but I intend to narrow the questions to a student question regarding the life cycle of the macro invertebrates and will have the groups select one of their favorite macro invertebrates and spend the remainder of the session with the assignment of creating a visual representation of the life cycle of that particular macro invertebrate. (The visual representation can be a poster, wheel, foursquare, etc.)
The third session will be a bit more guided. It will begin again with a class discussion regarding the environment in which the macro invertebrates live, its interaction with human beings and the cleanliness of the water. Based on their experience in the first session at the lake, I will have students discuss amongst their groups and rate the level of pollution they feel exists in the water. Next, I will hand out the charts that show the levels of sensitivity of macro invertebrates to pollution. The chart has 2 groupings of macro invertebrates, those that are pollution tolerant and those that are not. (That chart is attached.) Next, I will have the students go through and find as many of the macro invertebrates that they can identify on the chart. Based on the types of macro invertebrates found, they should be able to make a determination of the general pollution level in Lake Bemidji. As a group they will write a short summary detailing their findings. Macro Invertebrate Identification Key (Acrobat (PDF) 4.5MB Sep9 09) Pollution Sensitivity Chart (Acrobat (PDF) 82kB Sep9 09)
This lesson needs to begin with a thorough discussion about safety along the water's edge. Once that has occurred, a discussion should ensue with the entire class to discuss what students already know and what they wonder regarding Macro invertebrates. (K-W-L Chart) Next, students are introduced to the Macro invertebrate Identification Keys. (The link is provided below.) Students should work with either a partner or a group and familiarize themselves with the Identification Keys. Then, students wade into the water and begin collecting macro invertebrates. The macro invertebrates are placed in a dishpan that already contains some lake water. Once the students have collected a number of macro invertebrates they can leave the water and move to a site where they are able to work. At the work site the students should isolate individual macro invertebrates, make observations using hand lenses or microscopes, write and sketch their observations in their journals, and use the Identification Keys to identify them, this should also be recorded in their journals.
Once the students have identified their macro invertebrates and all information is recorded in their journals, then the students should create a list of questions that they have and a discussion should take place reviewing all that the students have learned to this point and should also create a list comprised of two or three of each of the groups questions. This is a good ending point for this class session.
The second session begins where the last one ended. Revisit the previous class discussion and the list of questions created. At this point, the lesson can take many different directions but I intend to narrow the questions to a student question regarding the life cycle of the macro invertebrates and will have the groups select one of their favorite macro invertebrates and spend the remainder of the session with the assignment of creating a visual representation of the life cycle of that particular macro invertebrate. (The visual representation can be a poster, wheel, foursquare, etc.)
The third session will be a bit more guided. It will begin again with a class discussion regarding the environment in which the macro invertebrates live, its interaction with human beings and the cleanliness of the water. Based on their experience in the first session at the lake, I will have students discuss amongst their groups and rate the level of pollution they feel exists in the water. Next, I will hand out the charts that show the levels of sensitivity of macro invertebrates to pollution. The chart has 2 groupings of macro invertebrates, those that are pollution tolerant and those that are not. (That chart is attached.) Next, I will have the students go through and find as many of the macro invertebrates that they can identify on the chart. Based on the types of macro invertebrates found, they should be able to make a determination of the general pollution level in Lake Bemidji. As a group they will write a short summary detailing their findings. Macro Invertebrate Identification Key (Acrobat (PDF) 4.5MB Sep9 09) Pollution Sensitivity Chart (Acrobat (PDF) 82kB Sep9 09)
Teaching Notes and Tips
Obviously much planning needs to go into the layout of the activity at the lake. I always have parent volunteers that assist me and bring along many supplies. In the classroom, I have wonderful library personnel that assist me in locating books at the reading levels of my students for their research.
Assessment
I use informal questioning and casual observations to assess the progress of my students at the lake. Again in the classroom, I observe and assist students as they begin working on their questions and beginning their research. Additionally, I plan to use the students' life cycle projects and their summaries for the final assessments.
Standards
Life Science 5.4.1 & .2
Students will discover that living things have a wide variety of characteristics that enable them to grow and survive in our world. Additionally, the students will learn that humans can impact the environment of these living things which may or may not be harmful them.
Students will discover that living things have a wide variety of characteristics that enable them to grow and survive in our world. Additionally, the students will learn that humans can impact the environment of these living things which may or may not be harmful them.