A Diversity of Guts

About this lesson

At the end of the dark ages, anatomy was taught as though everything that could be known was known. Scholars learned about what had been discovered rather than how to make discoveries. This was true even though the body (and the rest of biology) was very poorly understood. When the knowledge of antiquity was rediscovered during the renaissance, it was initially taken as gospel to be taught rather than a starting point from which further inquiry could continue. During dissections, a professor would stand and read from an anatomy book from antiquity (by Galen) and the students were meant to find in the body being dissected those features that were mentioned in the ancient text. The problem, though, a problem that seems silly in retrospect, was that the knowledge of antiquity was not perfect. If the students saw something in a body that was not in the text, that observation was to be discarded. The body could lie; the thousand-year-old book was true. Fortunately, beginning in the late renaissance, scholars began to add to and improve ancient knowledge rather than simply taking it as the complete and revealed truth. This break was revolutionary, but incomplete.

This lab allows scientists to learn from the thousands of animals that are dissected every year in biology, anatomy and physiology courses in both high schools and university labs. By completing several simple measurements and answering questions about specimens, students take a step that is 600 years overdue: we bring citizen science into the lab.


Lesson Plan
Lab Materials

How to participate

Get Started
Get Started

Get Started

Ready to learn about animal anatomy? Follow these steps to participate in our dissection lab. Illustrations by Chris Hedstrom.

Step 1
Step 1

Step 1

Download the "Frog Dissection" Presentation. Click on "Presentations" above to get started. Assemble the materials you need to get started.

Step 2
Step 2

Step 2

Start your dissection. This activity is one that has been done in classrooms for centuries... but now we will collect data on those animals and learn something more. Photo by Lauren Nichols.

Step 3
Step 3

Step 3

Follow the directions, cut out the guts. There are many things that we can learn by looking at the internal anatomy of animals, and lots of mysteries still remain. Once you have removed the digestive tract (more details in the presentations) take standard measurements and then...

Step 4
Step 4

Step 4

Send in your data. Complete the data form online (button below) with your students for each specimen and scientists will (finally) learn more about the digestive tracts of animals.

After completing the Measurements Form from this lesson, please input the written recorded measurements into this online form.

Enter Your Data Here

Materials needed

  • Preserved Rat (Item # 228305), preserved pig (Item #228384), preserved frog (item #227104) – Carolina Biological or any lab supplier
  • Dissection guides
  • General biology dissection kit
  • Dissection tray and pad
  • Dissecting pins
  • PPE including nitrile gloves, eye protection, and waste disposal
  • String
  • Soft metric tape measure (150 cm)
  • Ruler

Anatomy worksheets

Download and print these stylized anatomy worksheets! (Illustrations by Chris Hedstrom)

Color worksheet (PDF)
Black & white worksheet (PDF)

Bigfoot figure

Color worksheet (PDF)
Black & white worksheet (PDF)

Bigfoot and friend pig

Color worksheet (PDF)

Pig figure

Color worksheet (PDF)
Black & white worksheet (PDF)

Supporting Materials

Why should we care about this project?

All around the world frogs, pigs and rats are dissected in classrooms. The number of animals that are dissected is immense, in the millions. When these animals are dissected, no data are collected, ever. The animals are studied like the bodies of Renaissance humans and then discarded. This is particularly tragic if one remembers that most of what is knowable is not yet known, even with regard to frogs, pigs and rats. New discoveries await in the bodies of dissected animals, discoveries students could be making but are not, likely because neither they nor their teachers have even considered this as an option. The most interesting of these discoveries are the ones we cannot anticipate, but there are some we can anticipate.

Among the most challenging diseases of humans, and mammals in general, to study are rare congenital diseases. Collectively these diseases affect many individuals, but the genetic underpinnings of these diseases are hard to understand because, in order to know which genetic variants might cause one of these diseases, one needs to study the bodies and genes of many afflicted individuals.

A simple answer exists. When students study frog dissections, if they were to look for frogs with congenital problems, document those frogs, and take tissue samples of those frogs (which they or someone else could sequence), we could start to understand the origin of such diseases. Instead, most rare congenital disorders are not well understood and will not be for decades, and nothing new is learned from the millions of dead animals. There are barriers to implementing this example, but they are surmountable with the citizen science approach.

About the Scientists

Colleen Grant
Colleen Grant is a lab supervisor at North Carolina State University in the Biological Sciences Department. She has a masters degree in Horticulture Science and has worked in upper level biology teaching labs for 11 years. Courses she works closely with include Anatomy and Physiology, Animal Diversity and Ecology.
Amanda Hale
Amanda Hale is a graduate student in the department of Biological Sciences at North Carolina State University. She received her masters’ at NC State for biological anthropology. Her research is focused on both the relationship between ecology and morphological diversity in primate evolution and the taphonomic changes to bone in varying depositions. She has taught both Animal Anatomy and Physiology and Human Anatomy at NC State.

About the SciArt

Students Discover SciArt is created by Buzz Hoot Roar, the amazing team that brings science to life in their graphics-driven science blog.

About the Artist

Chris Hedstrom is a entomologist in Salem, OR, studying biological control for the Oregon Department of Agriculture. He’s also an illustrator and photographer. Check out new drawings, photos and writing as they appear at chedstrom.tumblr.com.

Extension Ideas

A Diversity of Guts: 4 Case Studies

Standards Alignment

NGSS Practices

1. Asking questions
3. Planning and carrying out investigations
4. Analyzing and interpreting data
5. Using mathematics and computational thinking
8. Obtaining, evaluating, and communicating information

Vision and Change Standards

Evolution: Ability to apply the process of science

  • Engaging students in the dissection so they have a better handle on identifying adaptive differences and/or anomalies in their specimens.
  • Having students identify deviations/variations from/of the basic plan in their specimens and develop questions and hypotheses about why they may exist (e.g., Are these stochastic alteration of the blueprint? Their appearance is due to adaptive changes to the basic vertebrate digestive system related to diet.)
  • A) Have them collect the standard data (discussed more below) and determine which data are applicable to testing their hypothesis and B) Have them do literature research to interpret hypothesis or identify blanks in understanding.

Evolution: Ability to use quantitative reasoning

  • Data Collection – would like a mix of discrete and continuous data collected (which to use could be instructor’s discretion) Variable options – small intestine length, cecum presence, cecum length, body size, body weight, body circumference, tooth size, tooth formula

Structure and Function: Ability to apply the process of science

  • Traditional identification of anatomical features
  • Relationship of each region of digestion anatomy with its’ function (this will also help them define hypotheses about variations from adaptation)