Inquiry-Based Lesson Plan Template

Comparative Anatomy Scavenger Hunt

Author: Sharon Kessler, ASU Fellow; & Trina Howard, Teacher, Lowell Elementary School

Target grade(s): 5th - 6th (but this lesson would also work well for 7th- 12th)

Time required preparing for lesson each time it is used: I recommend that the teacher dissect one of each of the specimens prior to the class – both to become familiar with the anatomy of each species and to have a ‘model’ should the students destroy theirs. This will cause the prep to be about an hour/specimen, however, if this is not done, then the prep will require approximately an hour for organizing materials.

Time required using or implementing lesson plan: Minimum of 6 days.

Equipment or materials needed:

1) Computers, one for every two students is ideal, but the lesson would also work with less computers. 2) Five dissection specimens per class: one fish, one frog, one bird, one snake, one rat. I recommend that the specimens be “double injected” if possible. This means that the veins have been injected with blue dye and the arteries with red dye. It makes it much easier for the students to identify separate structures. We ordered our specimens from Niles Biological, but other companies are also available. 3) Five dissection kits per class (scalpel, probe, scissors, dissection pan, pins, etc.) 4) Handouts of each species’ anatomy can be created from the websites listed in the file: Useful_websites.xls. 5) Student worksheet (provided) 6) Teacher check list of things students should notice (provided) 7) Goggles and gloves

Safety precautions that should be taken or pointed out:

Instructor should be sure to cover lab safety when working with sharp tools and the importance of showing respect for the animal even though it’s dead.

Focus question of the project How does the anatomy of the animals relate to their different habitats?

Overview

Students will research their animals and their habitats, dissect the animals, and consider how the anatomy of each is adapted to its environment. They will observe vertebrate internal anatomy and compare the fish, bird, rat, snake, and frog. They will consider how the similarities and differences they observe provide evidence for evolution.

Objective

Students will work in groups to research their animals to acquire background information, conduct a student-driven dissection, record their observations in diagrams, think critically about the relationship between anatomy and habitat, and communicate what they learned to their classmates both orally and with the diagrams. Students will explore concepts of evolution and adaptation.

Arizona State Standards

FIFTH GRADE: Strand 4: Life Science: Concept 1: Structure and Function in living systems: Students will explore and observe the internal anatomy of the nervous, muscular, skeletal, digestive, circulatory, and excretory systems.

SIXTH GRADE: Strand 4: Life Science: Concept 1: Students will learn to relate different anatomical structures across animals to their respective functions and they will learn how the various anatomical systems work together to perform functions vital to a living organism.

Lesson Plan Procedure

Assessing prior knowledge: This unit is designed to follow the fifth and sixth grade units on human anatomy. Prior knowledge can be assessed when students answer the worksheet question about what organs they expect to find (Question 3). A discussion can also be used as a review of human anatomy and to assess what they know about non-human animals.

Capturing their curiosity: Curiosity can be captured by introducing the dissection tools, showing the dissection specimens, and then having the students watch the virtual frog dissection video.

Student-driven inquiry: Student groups do a student-directed dissection of their specimen.

Assessment: Students can be assessed by the accuracy of their diagrams, how well they explain their findings to their fellow students, and by their worksheets.

DAY 1: Introduction (May require two days if classes are short, e.g. less than 75 min)

1) Introduce the concept of adaptation and explain how organisms that are best adapted to their environment will have more offspring and over time the population will have more individuals with those beneficial traits. Stress that these changes do not occur on an individual level, but within the population over time. Individuals do not develop changes because they NEED them, instead, over time, those individuals best suited to the environment have more offspring causing changes in the population. Ask students what they think will happen if the environment changes – like another ice age or global warming. Students should be able to predict that populations will have to adapt or go extinct. 2) Introduce the dissection tools and show them the specimens. Discuss good dissection techniques, stressing that students should be careful to only cut through one layer at a time and not dissect too fast because if structures get destroyed, they won’t be able to see and identify them. Be sure to tell the students not to dig the point of the scissors into the animal when cutting open the skin. If they dig the point of the scissors in structures underneath may be damaged. 3) Divide the class into five groups and let students pick which specimen they will dissect (though this may take some moderating because each class group needs to dissect a different animal). 4) Within each group, each student picks a system (skeletal, circulatory, digestive, excretory, nervous, muscular) for which they will be the “expert” in their group. This does not mean that the student will dissect that system, just that they will be responsible for explaining that system to their group and making sure their group members understand it. 5) Have students decide upon “classroom rules” for the dissection (safety rules, respect for the animals, sharing, etc.). 6) Play the virtual frog dissection for the students so they become familiar with dissection techniques:

http://www.mhhe.com/biosci/genbio/virtual_labs/BL_16/BL_16.html

DAY 2: Students research the animals online (May require two days if classes are short)

1) Have students do the fish dissection game (website listed in “Useful_websites.xls”) and research their animals online to learn about their habitats and their anatomy. Make sure the students understand that this background knowledge will help them recognize what the structures are when they find them. Discuss with the students the importance of looking at the source of the materials to evaluate the trustworthiness of a site. A list of useful websites is provided in the file: “useful_websites.xls.” Diagrams can be printed from these sites. Students should start researching their specimen, but also read about the others as well!

DAY 3: Dissection (May require two days if classes are short)

1) Students dissect their animals beginning by opening the animal themselves and then proceeding at their own pace, identifying structures as they go. Each table should have diagrams (printed from the websites listed in the file “Useful_websites.xls”) available to the students to help them identify the organs. Students may need to be reminded to start by pinning the animal down and then cutting through the skin on the ventral side. The frog, rat, and snake will be fairly easy to open. Students should pluck the bird on the ventral side before cutting through the skin. Students may request help in opening the bird’s ribcage. The fish can also be tough to open and students may request help with it as well. 2) As the groups are dissecting, the instructor can walk from group to group, helping the students dissect if they are stuck and asking what organs they have found so far. By the end of the class, all students should be able to point out the major organs in the digestive, circulatory, excretory systems as well as identify bones and muscle tissue. 3) After students have identified the parts of these systems, suggest that they may want to open their animals’ stomachs to see if there is any food there. (The bird group should open the gizzard and observe the sand and rocks used for mechanical break down of food). Students can also open the heart and identify the different chambers. Cutting around the lower edge and lifting up the top half will work best. If students have time, they may try to dissect through the skull to find the brain. 4) After students dissect the specimens, they should be wrapped in wet paper towels and put in plastic bags to prevent them from drying out over night. Specimens should be refrigerated.

DAY 4: Diagramming

1) Students examine the specimens they dissected the previous day and diagram the structures in their dissected specimens. Each student is the “expert” on a particular system and should verify that his/her group-mates have those structures correctly identified. This is a good time for the instructor to go around to different tables, observe the diagrams and make sure that the students have correctly identified the structures. If any group has destroyed their specimen, the teacher’s “model” specimens can be used.

DAY 5: Observing the other specimens

1) Students rotate through each of the tables and observe and identify the structures in each of the other organisms. The best dissected specimen should be available at each table as well as any organs that were dissected out further (heart, stomach, etc). If the instructor dissected out “model specimens,” those will probably be the best dissections and should be displayed. It will be helpful to also provide the printed diagrams so students can use them to identify structures. It is very important that the instructor go to each table with each group of students and verify that they have correctly identified the structures before they rotate again. The file “Things_students_should_notice.doc” can serve as a checklist to make sure each group has noticed the important differences in each specimen.

DAY 6: Adaptations

1) Students fill out the remaining questions on the worksheet. For question nine, each group can discuss the adaptations they found for their organism (ways that their organism suited to its environment), then each group can report to the rest of the class, and a tally of the total per class can be kept on the board. The class that reports the most adaptations wins the “Scavenger Hunt” and receives a treat the following day (ice cream, popsicles, or candy). Lesson Plan Assessment / Evaluation (Reflective Essay)

This lesson went really well. Students were extremely excited about it and very engaged. They took great care in dissecting slowly and carefully and as a result they were able to see a lot of the internal anatomy of their specimens. The students were so excited about it, that other teachers reported that they had difficulty getting their students to focus on other classes! During the introduction day, the last class of students didn’t want to leave school without watching the rest of the virtual dissection video. One student told me that her mother had planned to keep her out of school on dissection day, but she refused, telling her mother that she couldn’t miss it! We also had great interest in the lesson, both from parents who attended, and from other teachers in the school who stopped by to watch. Other teachers said they hoped the lesson would continue and be taught every year.

Using adaptation as the unifying “big idea” worked really well, even at this level where students have not yet had genetics or studied evolution in detail. Because students understand that offspring receive their genes from their parents, I did not need to go into great detail about the mechanics of evolution. Instead I focused on the role of the environment in creating a need for species to change over time. One area that I found I needed to be careful to stress was that individuals do not develop adaptations because they NEED them. Instead, populations randomly develop changes and some of them happen, by chance, to be beneficial in the environment and so, over time, individuals with those beneficial traits have more offspring than others causing that trait to increase in the population. The goal for tying in this concept to the lesson was to introduce the concepts and prepare them to learn about it in greater detail later when they have biology and genetics.

The biggest difficulty with the lesson was time. Since the class periods in our school are only 55 minutes long, each of the first three days described above, took two days. 90 minute class periods would be ideal, but if that is not possible, just making those parts last two days also works fine.

In our school we had five classes, but students dissected only three sets of specimens. Four classes shared. This allowed us to save money and also time. That meant that the first class to receive a set of specimens opened them. The next class identified the structures in the already open specimen and dissected the stomach, heart, and possibly looked for the brain. This worked well, but I think that if time and money permits, having each class do the whole dissection process would be ideal. However, should this time/money saver be necessary, each student still receives all of the information when they diagram the fully dissected specimen and compare it to the other fully dissected specimens.

Overall, I felt this lesson was extremely successful, that the students were highly engaged and that it strongly reinforced their previous lessons on human anatomy and pushed them to begin placing their knowledge in an evolutionary context. I would strongly recommend this lesson for any instructor teaching anatomy in grades 5-12. I think this lesson could be easily adapted to any age group, including high school biology.