In a previous lesson, students learned about what a salt marsh/wetland area consisted of. They watched several virtual trips through the marsh. (If your time of year and place allows, finding an actual wetland to visit can be so powerful here.)
Students researched an animal of the salt marsh and found out what it eats, what eats it, and where it finds shelter. They begin today by drawing an index card sized picture of their animal and labeling the picture.
I say to students, "yesterday you read all about an animal and you found out all about what it eats, and where it lives. Today I want you to start by doing your best to draw your animal and putting its name on the front of this card." I check for understanding and then give students about 5 minutes to draw their animals. When everyone is finished, I invite students to bring their cards and their research pages to the rug.
On the rug I have set 2 large, mural sized pieces of paper. One is blue to represent water, and one is green to represent the land areas of the marsh. I ask each student to place his or her picture on the proper habitat background with a piece of tape. "Today we are going to create a food web. I let students help us figure out that a food web is a connection of what each animal eats to other animals that it may eat or that eat it. The reason for using a food web demonstration is to help students see that the diverse animals of a habitat are dependent on each other for survival. By discussing our mural, students visualize the concept of a food web. Creating the Food Web
Next I ask, "does anyone see an animal on the mural that they know their animal eats?" I call on one student and ask them to tell us what their animal is and what it eats. I hand them a marker and ask them to draw a line from their animal to the animal it eats. "Does your animal eat anything else on the mural?" If yes I ask the student to draw another line to the new animal, if no, I call on the next student to repeat the process. Defining the Food Web
When everyone has had a turn I say, "I have some cord grass and some insects here. I am going to place them on the mural. Does anyone need to draw a line to either of these things?" I let students add lines to the grass and insects if appropriate.
"What do you notice about our mural now that we have all connected our animals to things they eat?" I am hoping that students will notice the interconnectedness of the animals living in the salt marsh.
I refer back to our TQL (think, question, learn) chart that we made in part 1 of this lesson. "Is there anything new that we have learned today that we should add to our chart? Are there any new question we want to add? Are there any answers to our questions that we should fill in?"
I want to make sure that students are connecting our lesson from yesterday to their new experiences with the food web today.
I want students to see the interdependence of the diverse life in a single habitat. I say to students, "look at how many of your animals eat the fish of the river. What would happen if people fished so much that all of the fish were taken out of the river?" As I say this, I remove the fish from the paper. As students comment on what might happen, I trace the lines connected to the fish back to the animal that eats the fish. I say, "look, the raccoon may be hungry, but he can still eat plants so he will still survive, but his diet will be limited and he might get a little sick. Look at the heron. It only eats fish. Oh no, that means that the heron will starve. There will be no more heron." I remove the heron from the paper. I continue this process with other animals, removing those that only eat a single creature, or talking about how the others won't have as much to eat.
When I have traced all the animals back to their food source, and removed all that have nothing to eat, I ask, "what do you notice about the animals in the marsh? Are they all the same? Do they eat the same thing? Do they need each other for survival?"
I let students answer each question, and ask more of their own questions which I post on our TQL chart. I encourage all students to take part in the scientific discussion by passing around a stuffed lobster. I say, "tell us what you notice about our animals in the marsh from our mural when the lobster comes to you. We want to see if each person can share one thing they have noticed today."
I add any new discoveries to our TQL chart.
To bring closure to this lesson I ask students to look at the TQL chart. I ask them if there is anything they want to add, or any questions they want to answer, or things we need to change as a result of our lesson today.
I ask one final question for students to address as they bring our activity to a close today. "Do you think animals in other habitats depend on each other as well?"
I ask students to take out their journals and write about what they know about how animals depend on each other in the wetland habitat. I collect the journals so I can assess student understanding of the diversity and interdependence of animals in a single habitat.