7. Flower and Frog Dissection

Sarracenia flower dissection: Image courtexy of Noah ElhardtSarracenia flower dissection: Image courtexy of Noah Elhardt Leopard frog in duckweed: Image courtesy of Steven DunlopLeopard frog in duckweed: Image courtesy of Steven Dunlop

Summary
To learn about the structure and function of living things, it is essential to explore the anatomy of real organisms up close and personal. While much can be accomplished by studying living things and their life cycles (see Raising Plants and Raising Trout projects), dissections offer a view of the internal structures and how they contribute to the whole. What follows are resources and information for teachers interested in conducting a flower and/or frog dissection. There are many excellent lesson plans and dissection guides on the web already. Rather than recreate these resources here, My Science Box provides nitty-gritty logistics and resources such as a selected list of great web resources, how to order frogs, what equipment you need, student handouts, and teaching strategies.

Objectives
Can identify the major parts of a plant and flower and describe the function of each part.
Can identify the major organs in a frog and describe the function of each organ.
Can thoughtfully, safely and respectfully complete an anatomical dissection.

Attachment Size
7dissections.doc 50.5 KB

7. Flower Dissection

Materials

  • Flowers, possibly of several different species for cross-species comparisons. Almost any flower may be used although the anatomy is more easily distinguished in some flowers than others. Some common flowers with clearly differentiated parts include:Sarracenia flower dissection: Image courtexy of Noah ElhardtSarracenia flower dissection: Image courtexy of Noah Elhardt
    • Lily
    • Iris
    • Daffodil
    • Tulip
    • Wisconsin fast plant
    • Peas
    • Poppies
    • Gladiolus
  • Paper plates/plastic trays
  • Scissors or razor blade (to open the ovary)
  • Hand lens
  • Optional: tweezers
  • Optional: dissecting scope

Teaching Tips
The best resource that I have found for flower dissections is Gertrude Battaly’s website. There you will find comprehensive background information, step-by-step dissection directions, discussion questions and more. I recommend using her handout for the clarity of the directions. The handout I have provided includes only a summary table and conclusion questions.

Sources
To learn more about flower anatomy, see the following websites:

  • The Wikipedia article on flowers has great scientific information about the anatomy and evolution of flowers.
  • Michele Kilmartin of Shenendehowa High School has good diagrams and photos of a daffodil dissection.
  • Texas Tech University’s Plant and Soil Sciences Department provides some excellent labeled photographs of flower dissections.
  • For good simple line drawings, see the Web Institute For Teachers, sponsored by the University of Chicago.

In addition to Gertrude Battaly’s site, other good lesson plans include:

  • A great cartoon-style interactive flower dissection can be found at BBC Kids. Some of the terminology differs between what is used on the BBC site and what is typically used in American classrooms.
  • San Diego State University has posted great lesson plans for a flower dissection followed by a fruit dissection. Solid scientific background information is found throughout the lesson plan.
  • Kids gardening provides a lesson plan appropriate for younger students.

Standards
Grade 7
Structure and Function in Living Systems
5. The anatomy and physiology of plants and animals illustrate the complementary nature of structure and function. As a basis for understanding this concept:
a. Students know plants and animals have levels of organization for structure and function, including cells, tissues, organs, organ systems, and the whole organism.
b. Students know organ systems function because of the contributions of individual organs, tissues, and cells. The failure of any part can affect the entire system.
f. Students know the structures and processes by which flowering plants generate pollen, ovules, seeds, and fruit.

Attachment Size
flower_handout.doc 31 KB

7. Frog Dissection

Materials

  • Frogs (order them from Carolina Biological catalog # 22-7444, 22-7445, 22-7446, 22-7464, 22-7465, 22-7466, between $3.35 - $5.95 depending on the quantity ordered and whether there is any color injection)
  • Paper plate or dissection tray
  • Scissors
  • Scalpel or razor blade
  • Forceps
  • Optional: dissection probes
  • Optional: dissection pins (especially useful if you have dissection trays on which to use them)

Teaching Tips
The best resource that I have found for frog dissections is Net Frog by Mabel Kinzie has a fabulous interactive virtual frog dissection including many multimedia resources such as videos and narration for every step of the dissection. It is an excellent resource for teachers, for students to preview or review the material, and as an alternative to an actual frog dissection.

Sources
To learn more about frogs, visit the following websites:

  • The Exploratorium had a great exhibit on frogs with excellent, student-friendly, web resources about frog behavior (listen to frog calls), biology (meet Dr. Tyrone Hayes, a frog researcher), and mythology (the Frog Prince and other stories).
  • The Amphibian Conservation Alliance provides an extensive set of articles on frog biology, behavior and conservation.
  • Check out the Animal Diversity Web, an extraordinary resource for learning about virtually any known species of animal. The site is organized by the classic kingdom-phylum-class taxonomy and includes photographs, diagrams, recordings of calls, and more. It is an indispensable resource for any class researching the classification of an organism.

In addition to Net Frog, other good lesson plans include:

  • The Virtual Frog Dissection by Steve Velie and Tim Hall is an exceptional resource, taking teachers and students step by step through a frog dissection and identifying structures both internally and externally. Their site was put together as part of a research study comparing the effectiveness of a virtual frog dissection versus an actual frog dissection. Every vocabulary word is linked to a comprehensive glossary of terms.
  • The Virtual Frog Dissection by Mrs. Mazanek of Batesville High School provides a similar virtual dissection experience using photographs and a glossary.
  • Lawrence Berkeley Labs has produced the Whole Frog Project, a 3 dimensional tool for dissecting a frog. They used MRI data from real frogs to allow users to rotate a digitized frog in 3 dimensions, while looking at only a selected set of organs. Teachers may find the labeled diagrams of selected body systems useful.

Standards
Grade 7
Structure and Function in Living Systems
5. The anatomy and physiology of plants and animals illustrate the complementary nature of structure and function. As a basis for understanding this concept:
a. Students know plants and animals have levels of organization for structure and function, including cells, tissues, organs, organ systems, and the whole organism.
b. Students know organ systems function because of the contributions of individual organs, tissues, and cells. The failure of any part can affect the entire system.
c. Students know how bones and muscles work together to provide a structural framework for movement.
d. Students know how the reproductive organs of the human female and male generate eggs and sperm and how sexual activity may lead to fertilization and pregnancy.

Physical Principles in Living Systems (Physical Sciences)
6. Physical principles underlie biological structures and functions. As a basis for understanding this concept:
j. Students know that contractions of the heart generate blood pressure and that heart valves prevent backflow of blood in the circulatory system.

Grades 9-12 Biology
Physiology
9. As a result of the coordinated structures and functions of organ systems, the internal environment of the human body remains relatively stable (homeostatic) despite changes in the outside environment. As a basis for understanding this concept:
a. Students know how the complementary activity of major body systems provides cells with oxygen and nutrients and removes toxic waste products such as carbon dioxide.
b. Students know how the nervous system mediates communication between different parts of the body and the body's interactions with the environment.
f. * Students know the individual functions and sites of secretion of digestive enzymes (amylases, proteases, nucleases, lipases), stomach acid, and bile salts.
g. * Students know the homeostatic role of the kidneys in the removal of nitrogenous wastes and the role of the liver in blood detoxification and glucose balance.

Attachment Size
frog_handout.doc 3.85 MB