Web of Life

Author: Christine Calahan

Organization: Texas A&M University

Topic: Ecosystems and Life cycles

Grade Level: 3rd grade

Time frame: 30 minutes

Overview: The following lesson plan involving insects will introduce ecosystems and life cycles to the students. The students will understand how each insect contributes to the overall web of life. This activity will take approximately 30 minutes and is intended for 3rd grade.

Purpose: The student will recognize the importance of insects in the web of life, construct a web of life that demonstrates the importance of the web of life and discuss the insects' role in the ecosystem. The student will recognize factors that change ecosystems.

Materials: 1 roll of yarn, nametags for each student, marker.

Getting Ready: The teacher needs to have a nametag for each student in her class. The nametags need to have a variety of animals, plants and insects on them, which each nametag being different. The teacher should also be familiar with all animals she includes on the nametags. This will allow for a motivating discussion of the organisms with the entire class.



Motivate (Engage): To introduce this activity the teacher should discuss with the students how important insects are to the web of life. Insects are predators and prey for many animals and without insects many animals would be extinct. Insects also do many important things for people and the environment. Have the students guess why insects are important (writing these on the board can help in this brainstorming activity). Students may answer production of silk, eat mosquitoes and other pests. Try to have the students think of reasons why many people do not like insects. This will lead into a discussion on how insects fit into our own ecosystem and a discussion of the three levels (autotrophic, heterotrophic and saprotrophic) of insects.


Activity (Explore): After discussing with the students why insects are important the class is ready to see for themselves.

  • Hand out nametags to all of the students.
  • Have the students stand in a circle and the teacher holding the yarn.
  • Have the students observe everyone's nametags and discuss the largest animals in terms of size and food consumption.
  • Start the yarn at the largest animal in the food web (possible deer) and have the students pass the yarn around going from largest animal down to the smallest insect (maggots, fruit flies, or termites) and then on the plants that the insects will eat. (Have the students keep in mind the food web idea) Each student will keep holding the yarn while it gets passed around.
  • Everyone should have a piece of the yarn that is connected to someone else. You have now created a web of life that incorporates large animals, insects and plants. Allow the students to talk about how everyone is connected. (No one should let go yet!!)
  • Have the students experiment with certain animals becoming extinct (they will drop their piece of the yarn). The students can visualize what happens when one part of the food web is gone and all of the animals that are affected by this change in the ecosystem.
  • Keep experimenting with different parts of the web being removed -what will happen if certain insects are removed from the web?

Safety Tips: There are no special safety tips for this lesson.

Concept Discovery (Explanation): The students will be able to see visually and learn about different ecosystems and how different animals and insects influence the web of life. By watching certain insects die and the web of yarn fall apart, the students will realize what happens to these animals when they encounter environmental changes that causes them to adapt, become ill or perish.

Going Further (Extensions): Students that would like to do another activity involving the web of life will be give construction paper and will be able life by linking construction strips together. They can then draw animals on the strips to represent the different hierarchy of animals and how they live off each other. Another extension would be to have the students discuss real life examples of how the removal of some animals and insects affects the overall web of life.

Closure: Summarize this activity by discussing with the students what they learned. Ask them what happens to the web of life when animals become extinct and how this has affected us in the past and how it will affect us in the future.

Assessment (Evaluation): Assess the student's knowledge about the web of life and ecosystems very Informally —by observation during the activity. Consider foregoing a test of any kind or a worksheet but ask different students questions during the activity. Based upon their answers, determine whether this activity was effective or not. Provide additional explanation to students if they seem confused.

Connections:

Mathematics:
Discuss the probability and what events are least likely, most likely, and equally likely to happen. This could be introduced when you discuss different environmental changes and whether or not they would affect certain insects. Which insects are more likely to become extinct or affect the web of life?
Language Arts (Writing):
Including journal writing is a great way to assess the information learned from students and to have students write their own answers to Rubric:

Questions asked:

Unsure

Sure

Comprehends

What does the web of life mean?      
What role do insects play in the environment?      
Why are insects important to the environment?      
What would happen if all insects died?