The Lesson Plan
We can learn a lot about the health of this place by looking to see what lives here. Finding out what kind of life is supported by the LAWS here will help give us even more information about the health of this place.
What do you think by just looking at the water? The bugs we see are aquatic critters we call macroinvertebrates, or macros for short. (ASIDE: Macro means large - visible with the naked eye - as opposed to micro - small, need a microscope to see it. The invertebrate part means its something that doesn’t have a backbone.) OK, now that we know a little about who we’ll be investigating, we get to be detectives/investigators again. I’ll be showing you the equipment we use to gather up these critters and how to do it so we don’t hurt them. Remember that they are very small and fragile.
- ask a formative assessment question such as “What lives here?” Have students begin to think about what lives in the pond as well as where that life can be found. Create a group list. See how the list changes by the end of the investigation.
- Read a related book: Pond Circle, McEllingot's Pool, Song of the Water Boatman, The Web at Dragonfly' Pond
- Do a scientific watercolor of the pond- you can even use some water from the pond in the art
- Allow students to free explore the space on the dam. What do they notice?
The investigation Question (student centered):
- This process can be done on the dam, but the amphitheater has fewer distractions for getting kids set up for the investigation.
- Show students the question (pre-written):
- What is the relationship between location and the number of types of bugs (macros)?
- Ask them to write the variables in their journal (p. 10 or 12)
- Ask students to write "location" at the top of the changed variable column. Write "Number of types of bugs" on the chart in the measured variable section.
- This is an opportunity to have a discussion with students about what a variable is and the difference between a changed and measured variable. Depends on what your goals are.
- Add the three locations to the chart. If short on time, you can give locations. If time permits, students can suggest locations. Possible locations: grass area, open water, mud area, floating classroom
The Investigation Procedure (Student Centered)
- Prior to passing out the dip nets or any other materials you should have a serious discussion with the students about respect for the plants, animals, self and their classmates at this place. Let the students know:
- Students will need to share and take turns with some of the materials
- Keep their feet dry - stay OUT of the water. Wet feet become cold feet, which will impact everyone in the group.
- Trampling plants to get the “best spot” hurts the animals since this is habitat for lots of critters
- The shoreline is a sensitive part of the ecosystem and is a shallow, warm place where lots of things live and plants grow—let’s walk softly here (demonstrate)
- The animals that we are catching today are very small and fragile and we are going to release them after we are done studying them- be sure you follow up and do this with your students.
- These animals cannot get the oxygen they need outside of the water
- We have tools to catch the critters so you can be gentle and effective when catching
- These animals will not hurt you, most of them are vegetarians and the ones that aren’t have teeth too small to nibble on you –but some of them do eat one another!!!
- Demonstrate how to use the tools
- Skim the top of the water. Keep the top of the water in the middle of the net. Nets can also be used to disturb the bottom mud area, and then skim across the surface. Be sure not to scoop up globs of mud as it will destroy the net.
- To safely fill the collection container with water, make sure there are three points of contact with the ground (knee of left leg, right foot, and left hand for example) while bending over to scoop up water.
- Establish boundaries
- Check for understanding in the group about procedures at location:
- Fill collection pan
- Swish net three times and empty it into the collection pan. Repeat for 2 minutes.
- When instructor says sort- the group uses spoons to sort critters into the ice cube tray compartments by type. (ice cube tray has water in it)
- When instructor says count- the group adds up the total number of types of bugs and records the amount in their journal.
- When instructor says rotate- the group returns the critters to the water, picks up all of their tools, and moves to the next location to repeat the steps.
- Divide students into three groups. Send groups to different locations. Send the Chaperone to one of the locations to assist or have them circulate helping all groups. If you have multiple chaperones, it can be nice to have an adult at every station.
- Keep track of time and manage the rotation of students through stations
- The clean up process can be a great time to take a brain and bathroom break before diving into the data.
- If students went on the floating classroom, take the personal flotation devices back to the pond shelter or arrange them on the dock if you know another group is using them later that day.
- Clear all nets by swishing them back and forth on the surface of open water
- Make sure all containers are empty of water and macros
- Take all materials back to the Pond Shelter or leave on the dam if you know another group is coming to use them
Data Analysis and Conclusion
- Using the amphitheathre or Pond Shelter can be a less distracting location for wrapping up the investigation (compared to the pond dam)
- Take out a large pre-written version of the investigation chart. Ask all groups to share their data. Once every group has shared out, all students should have 9 data points to work with.
- Ask students to find the average for each location in their journal. You may need to explain how to find averages. Let them write the number however their teacher is covering math (2 remainder 3, 2.4, 2 1/2)
- Once they have the averages, they can write their conclusion statements:
- There are more types of bugs at (location) with an average of (average #) types of bugs.
- There are fewer types of bugs at (location) with an average of (average #) types of bugs.
- There are more bugs at the (location) compared to the (location) by an average of (differences between the averages) types of bugs.
- I think there are more bugs at (location) because there was an average of (average #) types of bugs there.
- I think there are fewer bugs at (location) because there was an average of (average #) types of bugs there
- Once they have a minimum of two conclusion statements, make sure they show it to an adult who can review it. Send students back to make corrections as needed.
- Then they can find another person who has finished and compare conclusions. It is important that they understand that their conclusions are conversions of data into words- it is not a time for making inferences about why that specific data came out that way
- Based on your data, what conclusion did you come to?
- Was this how you thought the investigation would turn out? What surprised you?
- What could have influenced the data?
- If you could design your own investigation what relationship would you explore next?
- Why do you think these microorganisms live in water?
- Why might it be important for so many different kinds of microorganisms to live in the compost?
- What did you learn that you didn't know before?
- What new questions do you have?
- Do you think you could find any of these organisms back at home? Where would you look?
- Have you ever found any of these organisms before? Where?
- Is there a body of water like this one near your home? Could it also support macros? How could you find out?
- What might these macros tell us about the health of the water?
- Why do scientists collect this kind of information?
- What sorts of macros could you identify (call on students to name several)? Were there any not in the guides or the books? That’s very possible, as there are thousands, maybe even millions of macro invertebrates out there. How many different macros did we find today? Which do you think paints a healthier picture of our watershed: a diverse population of species or lots of the same species? Why or why not? Having a diverse population of macro invertebrates is a good thing, and it’s what we want to see for our waterway. Having a lot of different things means that there are a lot of different food sources and that different animals are using different resources in the watershed. If we had only a few species, it could be for a lot of different reasons. Can anyone think of some reasons why?
- Do you think the kinds of animals that we found here may change with the seasons? What things happen to water in the winter that is different than the spring? How might that affect the life that lives here?
- Many macros eat one another. Who else might depend on macros? That’s why it’s important that we learn as much as we can about the waterway here. Everything is connected to everything in an ecosystem, like our aquatic ecosystem here. Let’s pull out this chart and compare the critters we identified to see what it all means.
- Most likely we had a mix of organisms, some from every category, or at least some from the middle category. This is quite common. It does give us some answers though. Can you think of anything you saw here today that might be contributing to an unhealthy system? Is there anything that we can do to make things better? If we didn’t see any birds today, why might that be? Is there not enough of a food source for them, or no good habitat to live? Could we help them too?
- Go back to an assessment piece if there was a before and after
- Consider moving forward with some of their questions for an upcoming lesson
- Water Quality InvestigationWater Quality
- Pass out a hand lens to each student and ask them to draw a detailed picture of one of the critters in the water. Later give them a field guide to ID the critter.
- Take the macros to the lab to look at under the microscope
Relevant Journal Pages:
- Investigation planning and charts, pgs. 8-12
- "Water Quality Investigations", pgs. 20-21
- "Aquatic Macroinvertebrates", pg. 16
Macro invertebrates include aquatic worms, insects, clams, snails, and crustaceans. Macros can be adult invertebrates that spend their whole life in the water, or larval stages of insects, worms, or crabs. If we find immature or larval stages of macros, we must remember that they look different as larvae than they will when they are older. This series of changes to their bodies is called metamorphosis. We may have heard this word before when learning about the change from caterpillar to butterfly, or tadpole to frog. We investigate “macros” when we study water quality because they are generally easy to catch, are abundant in all sorts of waterways, and are very sensitive to environmental impacts. Identifying what macros are present can give us yet another piece of the puzzle on water quality. For example, we may find nothing but snails if the water is too polluted. If there are too many fish, we may not find too many aquatic insects at all—because they are a food source for the fish. We will see however, that a lot of these animals are tough! Several species of aquatic organisms have developed adaptations for their survival needs. Some have snorkels for breathing, and some have developed a huge tolerance (you’ll hear that word a lot) to things like how salty or cloudy the water is. Some even have been able to stand the environmental abuses of people (pollution) when we don’t take care of the environment the way we should. Macro invertebrates have it pretty rough sometimes. For starters, they are near the bottom of the food chain, where everything is trying to eat them all the time (though they are also predators to other organisms, such as plankton and each other). Macros are also very sensitive to chemical (pH for example) and environmental changes (temperature, turbidity) because they live in a fluid environment. Since they breathe underwater, they can’t just pack up and leave town when the going gets tough. Most macros also undergo incredible chemical and physical transformations as they shed their exoskeletons, grow wings and eventually fly or crawl from the water as adults. Most do not return to their childhood home until its time to lay eggs, where a new generation begins in the underwater world.