Note: Before the lesson, determine five cooperative learning groups for the jigsaw activity in Part 1.
Have students copy the graphic organizer below into their notes and complete it, placing themselves as the consumers in the center, and three producers that they eat in the other spaces. Call on several students to share their answers, and then briefly review the definitions of producer and consumer from Lesson 1. Add arrows to the diagram to show that energy flows from the producers to the consumer.
Tell students that there are many different kinds of relationships among organisms in ecosystems. The previous lesson, and this introduction, focused on feeding relationships. In this lesson, we will also examine various “symbiotic relationships,” in which two species live closely together.
Note: Remind students that a common misconception is that all symbiotic relationships are positive for both organisms. Mutualism, a relationship in which both organisms benefit from the relationship, is one of the many types of symbiosis.
Explain that first it is important to understand the levels of organization in an ecosystem. Have students copy the following graphic organizer into their notes, and title it “Levels of Ecosystem Organization.”
Define each term in the graphic organizer above. Elicit examples of each level from students, using a city park as an example for the ecosystem, and have students write down the examples in their notes.
Species Interactions Jigsaw Activity
Explain: “Since we have been talking about the various roles that species play in ecosystems, we need to look at how the different species interact with one another, and what roles they play in these interactions.” Tell students that they are going to participate in a jigsaw cooperative learning activity dealing with species interactions. Review the definition of a “symbiotic relationship.”
Divide students into five groups, and tell them that they are in their home groups. Now distribute Species Interactions Jigsaw Activity–Student Version (S-8-9-2_Species Interactions Jigsaw Activity-Student Version.doc), so students can follow along as you explain to them what they will be doing.
For this activity each member of the home group will go to one of five stations. At these stations, students will be given materials to read in order to understand a type of species interaction. While at these stations, they will be instructed to read over the definition and example for the interaction (S-8-9-2_Species Interactions Jigsaw Activity-Station Groups Materials.doc).
After reading the definitions and examples, students should talk with their station group to decide on how to put these definitions into their own words so that they will be able to explain them to their home groups. Have each student take notes on the species interaction because the notes will stay at the station and cannot be taken back to the home groups. Circulate during this time to answer any questions students may have.
Have each station group brainstorm and come up with at least one other example for the species interaction in order to better explain the term to their home groups.
After about ten minutes, collect the materials on each species interaction. Send students back to their home groups where they will have around 15 minutes to take turns explaining the species interactions they learned about to the other group members. Encourage students to put ideas into their own words to explain these concepts.
Have students take notes on what each of the home group members says about their species interaction. Tell them that they will be quizzed after the activity.
Have students put away their notes to prepare for a short quiz on the activity. Distribute the Species Interactions Quiz (S-8-9-2_Species Interactions Quiz-Student Version.doc), and have students complete it individually.
Show students the following food chain:
Grass → Rabbit → Fox
Ask students to identify the predator and prey relationship in the food chain. Have them predict what would happen to the rabbit population if most of the foxes were hunted and killed. Ask students whether that change could also affect the producers in the food chain.
Tell students that predator–prey relationships are important in ecosystems because they provide a balance between the populations. Explain that students are going to use some data to investigate a specific predator–prey relationship.
Distribute the Predator–Prey Lab Activity (S-8-9-2_Predator-Prey Lab Activity-Student Version.doc and S-8-9-2_Predator-Prey Lab Activity-Teacher Version.doc) and have students complete it independently.
- Students who might need an opportunity for additional learning can complete the Predator–Prey Lab Activity with a partner. Have each partner create a single-line graph (i.e., one for snowshoe hare data, and one for lynx data). Have the partners compare their graphs and work together on the analysis questions.
- Students who may be going beyond the standards can investigate the reintroduction of lynx in Colorado (S-8-9-2_Colorado Lynx Article.doc) or do an Internet search on “lynx” + “reintroduction.” Have students write an article for an imaginary newspaper on the subject.
- Have students who may be going beyond the standards conduct a debate or write a persuasive essay on whether hunting should be used for population control of animals such as the white-tailed deer in Pennsylvania.