Skeleton Keys: Bonified Biology

J. Brian Hauge, Peninsula College


This series of exercises focuses on: the importance of observation in science; the proper use of scientific terminology and writing; the interrelationships between anatomy and position in a food web or energy pyramid; the biology of exotic species; toxins in the environment; animal use; and, the evolutionary significance of each of these topics. It requires at least one lab period and three lecture periods with considerable out-of-class work and student presentations and discussions.

Learning Goals

Students completing this Teaching-and-Learning Activity will be able to:

  1. Use and construct a dichotomous key such as those used to identify animals, plants, etc. in biological studies.
  2. Understand and properly use anatomical/scientific terminology.
  3. Relate anatomical structures of animal remains to the functional ecology of the living organism.
  4. Explain the roles of various organisms in a food web or energy pyramid and the possible effects of removing those organisms from the ecosystem.
  5. Explain how an organism's place in a food web or energy pyramid can affect how various toxins accumulate in its body.
  6. Explain how exotic species get into an ecosystem, the effect(s) of exotic species in an ecosystem, and how/why control measures are used in an attempt to reduce or eradicate some exotic species.
  7. Address animal use from diverse perspectives such as harvest of native animals, introduction of exotics for the purpose of future harvest, animal production for human use, and animal rights as related to all of these.
  8. Relate all of these topics to the context of evolution.

Sustainability issues addressed in these activities include:

  1. Historical and current harvest of native species and the effects on populations.
  2. Bycatch: incidental destruction and waste that occurs in harvest of animals for human use.
  3. The introduction and production/utilization of exotic species by man and the possible effects on ecosystems.
  4. The effects of toxins in the environment (with special emphasis on our bioregion) on native species and ecosystems.

Skills and habits of mind I hope the activity will foster:

  1. Careful observation and recording of observations using appropriate terminology.
  2. Each student (and instructor) will recognize and respect the beliefs or all others in the class (and groups not represented in the class) regarding use of native and exotic/produced species, incidental effects of animal harvest, and animal rights. Several published articles and Web pages (a few of which are listed below) will be provided to the students.
  3. Students will become more aware of their place in the ecosystem and how their actions and activities affect other humans, other species, the ecosystem where they live, and the biosphere as a whole.

Context for Use

These activities are appropriate for introductory biology courses for science majors or non-majors, especially those with an ecology component. Portions of the activity could be useful in introductory zoology or environmental science courses. Students typically work in groups of three to four students for classes with lab sections of 20-30 students.

These activities can be spread out through several parts of the term as the various topics are covered. In a multi-term sequence of biology courses, the activity works best when ecological and sustainability topics are covered.

This exercise is transferable not only to other institutions that have an osteology collection (or access to quality photos, see note later in the section on reflections), it can also be modified to take advantage of other types of collections. For instance, a botanical collection could be used instead of a bone collection, but the "secondary" emphases may need to be changed. Perhaps the "toxins in the environment" segment is changed from a bioaccumulation focus to one of toxins used in plant production or weed control. Also, with a plant collection, the discussions and presentations on exotic species could certainly be more extensive than those when using a collection of mammal skulls.

Class time required for this set of activities is one to two lab periods (3-6 hours of class time) and two to three lecture periods (2-3 hours of class time) depending on amount of time instructor wishes to spend on each assignment. In addition, approximately two to four hours of observation, six hours of library and internet search, and four hours of report preparation will be required outside class time.

This activity was designed around a bone collection that is part of a reference collection being constructed for identifying faunal artifacts from archaeological digs. This set of activities could easily be adapted for use with an archaeology class by changing the topics from "current" environmental, sustainability, and human use issues to those of the people and organisms of the time the archaeological site was active. The sustainability and social issues of this activity are certainly applicable to any courses which address these topics.

Description and Teaching Materials

Learning Activities and Course Content

Learning Activity One

This process typically takes an entire lab period (sometimes two). The class as a whole is presented with a specimen - my favorite is Arnold, my pet boa constrictor (Boa constrictor). Using the dichotomous key from the book, Serpientes de Costa Rica (Solorzano, 2004), the entire class keys the snake out first to family, then to genus. Using the species descriptions in the book, we discover the species. This process takes about five minutes. From this exercise, students learn the following:
  1. the format of a general dichotomous key
  2. the importance of careful observation in science
  3. anatomical terminology and careful description/definition of terms
Next, the students work with 30 different mammal skulls spread out on the lab tables. Most of these skulls represent species native to our bioregion (from mice and shrews to elk and sea lions), but some are of exotic species (domestic cats and dogs, cattle, pigs). Students are asked to walk around the room, observe the skulls, and make notes of anatomical structures. As this process progresses, the instructor or students (armed with texts or labeled anatomical charts) will define terms that can be used in later parts of the activity. For example, the different types of teeth (incisors, canines, premolars, molars), whether some of these teeth (such as incisors or molars) are "ever-growing," a space with no teeth (diastema), the different between horns and antlers, whether the eye socket (orbit) is separated or not separated from other skull openings, etc. Then, as a class, we use anatomical structures and attempt to place the skulls into groups that may or may not represent different phylogenetic taxa. At this point, the instructor will identify each species represented and to which taxon (order) it belongs. Finally, each group of students (four students works well) will attempts to write a dichotomous key that keys out all of the skulls to the proper order and species. Groups can exchange keys and test each other's efforts.

Resources and Learning Activity Handouts

Student Exercise 1
Handout 1: Constructing and Using a Dichotomous Identification Key
This activity will utilize:
  1. A fairly extensive (and growing) osteology/shell/fossil collection at Peninsula College.
  2. Staff and resources at the NOAA Discovery Center and the Art Fierro Marine Life Center in Port Angeles.
  3. Peninsula College archaeology (and perhaps history) faculty. The ultimate goal of the museum collection at Peninsula College goes beyond teaching taxonomy and anatomy. We plan to continue adding to the collection; emphasizing species historically utilized by Native Americans of the Olympic Peninsula (fish bones and shellfish fragments certainly will be added). This will result in a reference collection which can be used to identify animal remains from archaeological digs (one of which is planned for the upcoming summer). We have already begun seeking permission to utilize the reference collection from the Ozette dig of the 1970s, which resulted in the collection of artifacts now found at the Macah Museum in Neah Bay. This will add two other components to the study which will be available to students wishing to continue work with the collection: the historical role of man in the environment (the "ecological indian" concept) and the effects of climate change (utilizing the 10,000 years or so of archaeological data available).
Handout 2: Skulls Used in This Exercise
Learning Activity 2: 20 Questions

Student Exercise 2
Handout 1: Evolution of Anatomical Structures of Mammal Skulls
This process typically takes one lecture period. To prepare for the lecture, students will need to spend some out-of-class time with the skulls (they are made available in a biology prep area). They bring with them a list of species each skull represents and its taxonomic information. They are asked to make careful observations of the skulls: What do you see? What kind of structures do you find on different kinds of skulls? How might these structures have evolved?
Student Exercise 3
Handout 1: Food Chains, Food Webs, Energy Pyramids & Toxins in the Environment

This process typically takes one lecture period. To prepare for the lecture, student groups will need to spend some time conducting library/internet searches for 1) food webs, 2) energy pyramids, and 3) toxins in the environment (each group could be assigned a different topic if this seems too much for one group). Each group then presents their findings, prompting discussions of how anatomical structures may indicate where in the food web an organism exists, numbers of different species based on energy in the ecosystem, why some species are more affected by toxins than others, and the evolutionary significance of each of these topics.
Student Exercise 4
    Handout 1: Exotic Species, Sustainability of Animal Use, and Animal Rights

    This process typically takes one lecture period. To prepare for the lecture, student groups will need to spend some time conducting library/internet searches for 1) how exotic species get into an ecosystem and their possible effect(s) on the ecosystem and how/why control measures are used in an attempt to reduce or eradicate some exotic species, 2) the pros and cons of harvesting native animals, 3) introduction of exotics for the purpose of future harvest or animal production for human use, and 4) animal rights as related to all of these (each group could be assigned a different topic if this seems too much for one group). Each group then presents their findings, prompting discussions of how exotic species affect food webs and ecosystems, how and why native and exotic animals are harvested and effects this has on an ecosystem, and animal rights as related to use of native and exotic animals. Again, the evolutionary significance of each of these topics should be addressed where possible.

    Student Products
    Group (3-4 students) dichotomous keys; individual reports (written or verbal) on evolution of anatomical structures of mammal skulls, food chains/webs and energy pyramids, toxins in the environment, the effects of exotic species, and animal use/animal rights. Students could produce written reports or groups of students could prepare a PowerPoint presentation for each of these topics. For a science majors' course, I would expect a more sophisticated paper/presentation.

    Constructing and Using a Dichotomous Identification Key (Microsoft Word 73kB Oct27 11)
    Skulls Used in This Exercise (Microsoft Word 100kB Oct27 11)
    Evolution of Anatomical Structures of Mammal Skulls (Microsoft Word 668kB Oct27 11)
    20 Questions (Microsoft Word 28kB Oct27 11)
    Food Chains, Food Webs, Energy Pyramids & Toxins in the Environment (Microsoft Word 2007 (.docx) 13kB Oct27 11)
    Exotic Species, Sustainability of Animal Use, and Animal Rights (Microsoft Word 495kB Oct27 11)
    Grading Criteria (Microsoft Word 75kB Oct27 11)

    Teaching Notes and Tips

    Notes, Reflections, Cautions, and Special Suggestions

    This activity is based on the Peninsula College osteology collection which was first conceived in the 1970s (much of the material was collected then). Something very similar could be based on other such collections - such as a botanical (herbarium) collection, a marine invertebrate collection, a fossil collection, etc.

    The initial "lab" exercise (constructing a dichotomous key) is a very good way to get students to start thinking about the process of science, the language of science, and the importance of careful observation in science. I recommend this activity, using whatever specimens are available (I have had my students construct keys to key out each student in the class), as an introductory lab at any level of teaching. That said, it is not an easy task to get students to construct a functional, non-ambiguous dichotomous key. It often takes three or four attempts before they catch on that the process is quite simple if they pay attention to detail.

    Some Observations and Suggestions Include

    The first activity, constructing a dichotomous key, often poses a problem for students as they "don't know where to begin." It is important to emphasize that they can begin anywhere - and demonstrate this by using starting points from several of the groups who aren't having problems (they will likely be quite different).
    1. It is also possible to do the first exercise without any physical access to real skulls. There are a number of websites where quality photos of skulls, taken at two or more different angles, can be obtained.


    In the first part of the exercise, student learning will be documented by proper use of anatomical terminology and the production of a working dichotomous key.

    For subsequent class meetings, students will be required to conduct library or Web searches for a variety of topics (food webs and energy pyramids; bioaccumulation and persistent toxins found in our area; effects of exotic species; ethics and ecological effects of hunting, mass harvest, domestication and meat production; and animal rights). They will be required to turn in written or diagrammatic examples, short essays, and position papers (often requiring them to take a side other than their personal opinion). These works will be graded by the instructor and by peers to assess student learning and understanding.

    Traditional quizzes and exams will also be used to assess student learning.
    A before/after assessment could potentially measure student learning outcomes.
    A document with the following information explaining my grading criteria is given to students at the beginning of each term:

    References and Resources


    Honeyman, M.S., 1996. Sustainability Issues of US Swine Production. J. Animal Sci. 74: 1410- 1417.

    Jones, Gwyneth. Scientific Method Exercise. Bellevue Community College.

    Monterey Bay Aquarium. What's Troubling Our Waters: Bycatch Fish and Animals Caught and Wasted.

    Monterey Bay Aquarium. What's Troubling Our Waters: Bycatch Solutions.

    Solorzano, Alejandro. 2004. Serpientes de Costa Rica: Distribucion, Taxonomia, e Historia. Instituto Nacional de Biodiversidad (INBio).

    Sustainability Report.Org. Pollutants, Sustainability, Health, and Environment.

    University of Toronto Coalition for Animal Rights and the Environment (CARE).


    Thanks to Art Fierro, Delbert Gilbow, Ed Tisch, Albert Martin Tenebrae, and a host of students who collected and prepared the many dozens of skulls and associated skeletal material that make up the Peninsula College Osteology Collection and my many students in BIOL 100L, ZOOL 101L, and BIOL 221L who helped develop this activity through their participation in my classes. Thanks to George Middendorf and Charles Nilon for supplying a learning activity template (from their "Crosstown Walk" activity). I also used the OTS 20 Questions exercise (suggested by George Middendorf and Charles Nilon in "Crosstown Walk" and gleaned from the internet at Gwyneth Jones' site) to guide the second portion of the exercise.