Make a Frog Sandwich
A constructive introduction to dissection
modified by Janet Bowersox from:
Turtox frog booklet activity (~20 years old)
Elson, L. (1982). The Frog. Zoology Coloring Book (pp.79-86)
Coloring Concepts, Inc.
Type of Entry:
- individual project/lesson
Type of Activity:
- group/cooperative learning (spontaneous or structured)
- dissection preview lesson
- Life Science
- Special needs - ESL
- Special Education
Notes to Teacher:
I have used this with a variety of students and I am always amazed at how much high school students like to color, cut and paste! Nearly every student completes the Frog Sandwich and in the process, each of them learns some anatomy.
Required of students:
Each student assembles a paper Frog Sandwich over a one week time period. They exchange frogs to check, correct, and "sign off" on each other's work. After completing the dissection of preserved frogs, students take a station lab practical exam. They are allowed to use their frog sandwich on the exam as an identification guide and they submit their Frog Sandwich as part of their exam.
The one to two hours of preparation time involves making photocopies of the booklets, assembling materials, ordering preserved frogs, colored pencils, and locating books with good frog anatomy diagrams to assist students in labeling.
Class time needed:
Allow three class periods for work on the Frog Sandwich. The first period is to start labeling and coloring the organs. Students are expected to complete this as homework over several days. Allow one period for assembly of the Frog Sandwich booklet, and one period for students to check, correct, and sign off on each other's work. Additional class periods are needed for dissection, review, and exam.
For the students who ask, "Do we get to dissect in Biology?" or those who ask "Do we have to dissect in Biology?", the Frog Sandwich lets students choose how they will learn some comparative anatomy. The Frog Sandwich is a 5 page frog-shaped booklet of drawings depicting frog exterior dorsal view, skeletal system, internal organs, ventral muscles, and exterior ventral view. On each page, students color and label the organs, then cut out the parts and assemble their Frog Sandwich booklet. Students exchange frogs to check, correct, and "sign off" each other's work.
After completing their Frog Sandwiches, students choose to either personally dissect a frog, or to observe the anatomy of a pre-dissected frog. Models, laser disc, and Internet Frog dissection are also available for study. Students are allowed to use their own Frog Sandwiches as an aid to identification on a Lab Station Practical Exam, and they submit their frogs as part of the exam.
Since they already know organ location, relative size and shape before they ever look at the preserved frog, students are able to work more independently in the lab and are able to help each other to locate organs. There seems to be more attention focused on the anatomy, and less fooling around. And, instead of using 75 frogs/150 students, 20 frogs/150 students is sufficient.
What question does the activity help students to answer?
- What is inside a frog?
- What do the organs do?
- How is the anatomy of a frog similar/different from a human?
- print 1 booklet for each student (create template for frog sandwich booklet using illustrations such as those found in the Zoology Coloring Book, Coloring Concepts, Inc. Be sure to have a page for external anatomy (dorsal view); skeletal system (dorsal view); digestive system, urogenital system, circulatory system, muscular system (ventral view); and external anatomy (ventral view.)
- sets of colored pencils, scissors, magic tape to attach organs, stapler
- reference books or class room charts showing labeled frog anatomy
- Optical Data Life Science video disc, Bio Sci II video disc show dissection views
- Internet frog dissection http://george.lbl.gov/ITG.hm.pg.docs/dissect/info.html
- Zoology Coloring Book by Lawrence Elson
Have students label appropriate structures on each level of the sandwich. Then have students color illustrations and cut out all layers. Assemble layers in order and staple to form sandwich.
Method of Assessment/Evaluation
Students exchange their booklets to check, correct, and "sign off" on each other's work.
I set up a 35-40 station lab practical exam using the 20 class dissected frogs, models, toy frogs, and skeletons with one question/station. Questions relate not only to frog structures, but also to the other representative organisms studied in a unit on Animal Physiology. Students bring their own Frog Sandwiches to the exam to use for reference, and then turn in their Frog Sandwiches as part of the exam. Most of the students actually like taking the exam! Students gain confidence using their Frog Sandwiches on the exam, but with 1 minute/station, it is not an easy exam!