Cutting Edge > Courses > Paleontology > Teaching Activities > When Pond Scum Ruled the Earth - The Proterozoic Fossil Record

The Proterozoic Fossil Record

Julie K. Bartley
,
Gustavus Adolphus College

This activity has benefited from input from faculty educators beyond the author through a review and suggestion process.

This review took place as a part of a faculty professional development workshop where groups of faculty reviewed each others' activities and offered feedback and ideas for improvements. To learn more about the process On the Cutting Edge uses for activity review, see http://serc.carleton.edu/NAGTWorkshops/review.html.

This activity was selected for the On the Cutting Edge Exemplary Teaching Collection

Resources in this top level collection a) must have scored Exemplary or Very Good in all five review categories, and must also rate as “Exemplary” in at least three of the five categories. The five categories included in the peer review process are

  • Scientific Accuracy
  • Alignment of Learning Goals, Activities, and Assessments
  • Pedagogic Effectiveness
  • Robustness (usability and dependability of all components)
  • Completeness of the ActivitySheet web page

For more information about the peer review process itself, please see http://serc.carleton.edu/NAGTWorkshops/review.html.



This page first made public: May 25, 2009

Summary

In this specimen-based activity, students examine microfossils and stromatolites and build an understanding of the Proterozoic paleontological record.

Used this activity? Share your experiences and modifications

Context

Audience

Introductory historical geology course or undergraduate paleontology course.

Skills and concepts that students must have mastered

Basic modes of fossilization; survey of sedimentary rock types; rules for sketching hand samples

How the activity is situated in the course

Second laboratory exercise in the "fossil record" portion of the historical geology lab; in a paleontology course, this activity would be combined with other pieces examining the microfossil record of the Proterozoic

Goals

Content/concepts goals for this activity

Conceptualization of an environment dominated by microorganisms (the Proterozoic), and particularly to understand the differences between the environment at a single time slice (e.g., seafloor at a point in time) vs. the geologic structure produced over time (e.g., accumulated layers of a stromatolite).

Higher order thinking skills goals for this activity

Analysis of spatial data: relationship between 2-D and 3-D structures. Evaluation of the importance of variables in producing observed structures.

Other skills goals for this activity

Writing: brief descriptions of observations, posing hypothesiss. Drawing: creating simple representations of complex rock structures.

Description of the activity/assignment

In this laboratory exercise (2 hours), students explore the Proterozoic fossil record by examining two samples of microfossils, preserved in chert) and numerous samples of stromatolites. The laboratory exercise coincides with lecture discussions on the early history of life, and serves to illustrate the paleontological record of the Proterozoic. This exercise is the first laboratory exercise in the course that asks students to engage with and speculate upon the environmental and biological causes of the observed fossil record. The students' goal is to be able to identify some of the main environmental factors that combine to produce the diversity of stromatolite forms.

Determining whether students have met the goals

Students have conversations during the lab exercise, in which they propose hypotheses to explain their observations about stromatolites. Students hand in the product of their exercise and it is evaluated. Finally, students answer questions about stromatolite construction and microfossil preservation on the midterm exam.

More information about assessment tools and techniques.

Download teaching materials and tips

Other Materials

See more Teaching Activities »