Where on Earth were the reefs through geologic time?

Alycia L Stigall, Ohio University-Main Campus
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Summary

Students explore the geographic distribution of reefs through geologic time. Students map fossil occurrences of reef forming organisms on modern and paleogeographic reconstructions using the Paleobiology Database. Students will use these data to identify that, although the dominant reef builders have changed through time, the geographic position of reefs ecosystems through time has been stable.

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Context

Audience

To be used in an introductory undergraduate course, including (but not limited to) physical geology, historical geology, etc. Would also be appropriate for Grade 8 Earth Science.

Skills and concepts that students must have mastered

- Introduction to uniformitarianism
- Summarize the geologic timescale
- The basics tenants of plate tectonics and development of paleogeographic reconstructions
- Basic understanding of reef ecosystems (framework building, high diversity, warm water ecosystems)

How the activity is situated in the course

Stand-alone exercise that could be deployed early in the semester to expose students to authentic data and provide a mechanism to analyze this data while considering foundational concepts (plate movement, change through time in biota, evolutionary processes) in geosciences.

Goals

Content/concepts goals for this activity

Students will:
- Learn to use the navigator interface of the Paleobiology Database Navigator
- Evaluate taxonomic uniformitarianism
- Compare modern coral biology with ancient distributions
- Consider how paleoclimate and tectonic positions impact reef distribution
- Test hypotheses about environmental tolerance (mainly warm water) though time

Higher order thinking skills goals for this activity

Students will be able to:
- Plots occurrence data using data and tools from PBDB Navigator
- Rotate occurrence data onto paleocontinental reconstructions using tools from PBDB Navigator
- Analyze the latitudinal ranges of fossil corals (Orders Scleractinia, Tabulata, Rugosa) through time
- Analyze the latitudinal ranges of archaocyathid sponges (Class Archaeocyatha) and rudistid bivalves (Order Hippuritida) through time
- Evaluate how geographic distribution is related to paleoclimate and tectonics

Other skills goals for this activity

Students will be able to:
- Use of online database platform
- Map reading to aid in understanding paleogeographic reconstructions
- Plotting data
- Critical data comparison
- Integration of occurrence and climate data
- Hypotheses testing

Description and Teaching Materials

Students will learn to access data stored in the Paleobiology Database to generate maps of fossil distribution and paleogeographical reconstructions. They will use this data to examine the geographic distribution of reef ecosystems through time and assess the assumptions of uniformitarianism and the impact of climate and tectonic configurations on fossil distribution.

This activity is intended to be used in the classroom setting which would facilitate discussion of specific questions and sharing out of hypotheses generated. However, it can be used also as a homework activity completed independently by students. Total time for the activity should be 1 to 1.5 hours.

For in-class work, students can work either alone or in pairs (with pairs encouraged). Students will need the activity handout. Each student or student pair will need access to a laptop or desktop computer connected to the internet, running an internet browser.

It would be helpful for the instructor to demonstrate how to plot a taxonomic group per time period. For example, Dinosauria during the Jurassic. A tutorial is available online at https://www.youtube.com/watch?v=db2He3p-Jco


Student Handout for Reefs Through Time activity (Microsoft Word 2007 (.docx) 277kB Jun19 18)

Teaching Notes and Tips

For introductory classes, it would be useful to distribute a blank globe outline with the equator and 30 and 60 degrees N and S marked as lines so that they can use this for a frame of reference when eyeballing data to fill in their tables. For more advanced classes, students could download the data using the download tool in navigator and record "real" minimum and maximum latitude values.

To extend the activity, students could research or hypothesize additional reef-forming groups through geologic time and test for their correspondence to the tropical pattern. The lesson could also be extended by comparing reef-forming and non reef-forming groups, such as brachiopods or trilobites through time.

Assessment

Formative assessment occurs as groups are working. Instructor circulate and provides assistance and feedback.

Summative assessment of answered questions.

References and Resources

Paleobiology Database:
www.paleodb.org

climate graph: https://en.wikipedia.org/wiki/Paleoclimatology#/media/File:Phanerozoic_Climate_Change.png

Reef base:
www.reefbase.org

Various Wikipedia pages that provide images and explanations for the various clades explored:
Scleractinia: https://en.wikipedia.org/wiki/Scleractinia
Tabulata: https://en.wikipedia.org/wiki/Tabulata
Rugosa: https://en.wikipedia.org/wiki/Rugosa
Archaeocyatha: https://en.wikipedia.org/wiki/Archaeocyatha
Rudist bivalves: https://en.wikipedia.org/wiki/Rudists