Lesson Plan 6: Observing the Catalpa Sphinx Caterpillar

by Brenda Hunt
8th grade biology teacher
Habersham County

drawing paper, colored pencils or crayons, magnifying glass, string or paper fastners, hole punch, ruler, balance ( scale for weighing caterpillars), calculator, appropriate activity sheets for varying ability levels: predrawn charts for weights and length as well as predrawn axes for graphs of data ( for younger students the teacher may set up charts on board and have students help to fill them in verbally), pictures of scientists of both sexes, several races and doing different jobs, pictures of caterpillars that have poisonous or irritating hairs, Catalpa caterpillars and Catalpa leaves or tree, rearing containers labeled by number (naming the caterpillar might make the potential loss/ death of the caterpillar harder for the students).

Students will make a log book to record observations of caterpillars and Catalpa trees as they follow the life cycle. Students will do quanitative and qualitative observations. Students will learn to use a balance, ruler and magnifying glass. Students will role play as scientists and learn about the jobs of scientists. Students will learn about growth rates, observe stages of metamorphosis, discuss mimicry and learn to work cooperatively in groups. Teachers will determine what parts of the activity the students will be able to do themselves and what parts the teacher can model for them to obtain the desired results.

Step One:
The teacher might want to begin by asking students to draw or describe a scientist. Most students will describe a stereotypical image of a man with glasses in a lab coat, etc. Teacher will introduce pictures of scientists of a variety of races, variety of jobs and both sexes. Students should be asked to make observations about the pictures. The teacher should point out that they are going to be scientist like the ones in the pictures during this project . They will make observations just like scientists. Students should be lead to understand that everyone can use the skills of scientist such as observing, inferring, hypothesizing and solving problems or finding answers to questions. Teachers will want to point out how science, math and writing are interrelated and explain how a log book will contain writing and graphs.

Step Two:
Have students try to draw a caterpillar. These pictures can help the teacher determine the extent of a students experiences with caterpillars and any reservations or fears of caterpillars they might harbor. These are meant as a pretest and affective measure of attitude toward the caterpillars. Retain these for use at the end of the project. You might let students discuss the pictures and explain them.

Step Three:
Introduce the caterpillar to the students by first passing around the pictures and showing the slides of the caterpillar and the Catalpa tree. Attempt to have students observe features such as head, body, true and false feet as well as color and size at different ages and the "horn " on the back. The teacher can write their observations on the board then allow them to brainstorm inferences on their observations; in other words, why are these structures important for the caterpillar?

Step Four:
The teacher should show students how to handle the caterpillars gently and allow one to crawl across the teacher’s hand to show them it will not hurt them. Volunteers should be allowed to touch the caterpillars. Students should make observations of the caterpillars and be allowed to use the magnifying glass. The observations should be written in the first page of the log book along with an inference about why the structure is important. These may be written on the board. Students should be allowed to sketch the caterpillar and color it. The teacher should show students pictures of other caterpillars that are not safe to handle and talk about how this helps them to survive. Pointing out the “horn’ on the Catalpa caterpillar as a scary, but not harmful mimicry device can lead to further discussion about insect mimicry. Teachers can share pictures of other types of mimicry among animals.

Step Five:
Each caterpillar is to be weighed and measured for length and width. Then the data recorded in the data charts. Younger students can make measurements using the length of their finger or marks on a sheet of paper that can be compared to a ruler by the teacher. Students can be asked to make a simple hypothesis about how the caterpillars will change over the next 6 weeks and enter this into the log book. A class log book or scrapbook can be made in cases of younger children. Allow the students to redraw and color the caterpillar they are observing and if applicable write the name "Catalpa Sphinx Moth Caterpillar Project Log Book" and use this as the cover for their log book.

Step Six:
Once a week students should be allowed to make quantitative observations or measurements and make qualitative observations as well as draw the caterpillars. Students could take photographs to allow them to produce a mural, bulletin board and inspire writing activities. Zap cameras for use with the computer can be used or instamatics allow for quick results. You might want to assign a certain number caterpillar to a heterogeneous group of students to follow. Caterpillars will need a fresh supply of Catalpa leaves throughout the observation period so a source for this must be located before the beginning of the project. Check for other sources in your area; especially ask fishermen and students where to find the caterpillars and the trees; bait and tackle shops can be of assistance.

Other suggestions:
Teachers may use charts with students or model behavior and maintain them for them. Adapting the charts for younger students or using photographs instead of written descriptions can be done. Charts blown up or used as an overhead or written on the board and filled in by the teacher or students are alternatives. Using marks on strips of paper and comparing relative length can be used with very young students and making circles that become larger around for relative width is another option.

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