Work Sample & Commentary: Owl Pellets

The task
After a study of structure and function, students were asked to dissect owl pellets and to reconstruct the skeletal remains of animals contained within.

This activity is followed by a research report which includes the following information:

  • Owls as predators,
  • Conclusions about the diet and habit of the owl that made the pellet,
  • How scientists determine the predatory structures and behaviors of dinosaurs, and
  • A bibliography of books and internet sources used to compile the report.

After completing the dissection activity and the written component, students designed a labeled pictorial food web showing nutritional hierarchy based upon their analyses of their owl pellet.

Note: Commercially available owl pellets are sterilized and do not present a health or safety problem.

Circumstances of performance
This sample of student work was produced under the following conditions:
alone in a group
in class as homework
with teacher feedback with peer feedback
timed opportunity for revision

This work sample illustrates a standard-setting performance for the following parts of the standards:
a Life Sciences Concepts: Structure and function in living systems
d Life Sciences Concepts: Populations and ecosystems.
b Scientific Thinking: Use concepts from Science Standards 1 to 4.
f Scientific Thinking: Work individually and in teams.



What the work shows
a Life Sciences Concepts: The student produces evidence that demonstrates understanding of structure and function in living systems, such as…whole organisms, and ecosystems.
Based upon their analysis of owl pellets and follow-up research, students designed a labeled, pictorial food web showing a nutritional hierarchy.
The written “Analysis of Food Web” provides further evidence of understanding of structures and functions in an ecosystem.
The conclusion about the diet of the owl that produced the pellet the student dissected is based on careful observations , and indicates an understanding of the predator/prey relationship between an owl and a shrew.

d Life Sciences Concepts: The student produces evidence that demonstrates understanding of populations and ecosystems, such as the roles of producers, consumers, and decomposers in a food web….
The conclusion provides evidence of this understanding when it relates physical structure to predatory role.
Additional evidence is provided by the table that organizes research into the ecological roles of organisms whose remains were found in the owl pellet.

b Scientific Thinking: The student uses concepts from Science Standards 1 to 4 to explain a variety of observations and phenomena.
The conclusion accurately applies Science Standard a, especially as it relates jaw structure to diet.
The table showing the organization of the food web accurately applies Science Standard d.
Students successfully applied Science Standard a when they assembled the bones found in the pellet, and added the descriptive notes about physical structures to the left of the diagram.

f Scientific Thinking: The student works individually and in teams to collect and share information.
Throughout this investigation, students worked in groups to analyze the food web and to assemble the bone structure of the organisms that the owl ate. Use of the words “our” and “we” in and clearly indicate that this was a team effort.