Teaching About Time Using Timeline Activities in a Multi‐Disciplinary Course on North American Environments for Non‐Science Majors

Marguerite S.E. Forest, Department of Marine and Ecological Sciences, Florida Gulf Coast University

My background in environmental geography has provided me with some experience related to teaching and learning about temporal concepts. Graduate courses included classic works that dealt with human impacts over time, from Man and Nature: Or, Physical Geography as Modified by Human Action by George Perkins Marsh (1864), to Man's Role in Changing the Face of the Earth edited by William L. Thomas (1956), to Changes in Land Use and Land Cover: A Global Perspective edited by William B. Meyer and B. L. Turner (1994). As I began my own research about environmental alterations on Haida Gwaii in British Columbia, it became clear that all discussions about anthropogenic changes should be put into the context of natural variations that extend over much longer time frames. This required additional exploration of related disciplines like geology, paleoclimatology and paleoecology, and evolution. Now, I try to include such comparative temporal perspectives into all my environmental geography courses, at global, continental, and regional spatial scales.

I really enjoy good quality narrative and descriptive nonfiction books that tell amazing real stories about changes over time. For example, Peter D. Ward's books such as Rare Earth, (2003), Life and Death of Planet Earth (2004), Out of Thin Air (2006), Under a Green Sky (2008), and Flooded Earth (2010) are good examples of this genre. My students are required to read such books in addition to textbooks and the usual scientific articles. However, this approach was not sufficient to meet the enormous challenges that seem to be inherent to teaching and learning about temporal concepts. Without additional guidance, students seemed unable to transfer and use temporal information accurately, for example place key events of different types and from different sources into correct sequences in their own narratives.

My current strategy, designed to begin meeting these challenges, is to make explicit use of timelines. For my course on North American Environments, often taken by non-science majors with no previous science courses, I now provide an Excel spreadsheet with multiple worksheets on different topics to be covered in the course. Each worksheet consists of sets of short vertical timelines organized by orders of magnitude suitable for each topic. For example, Geology has timelines for Billions of Years, Hundreds of Millions of Years, and Tens of Millions of Years; Paleoclimate has Millions of Years, Hundreds of Thousands of Years, Tens of Thousands of Years, and even Thousands-Hundreds of Years; Weather has only Tens of Years and Years. Timelines for topics in the other worksheets are anchored to these same "Powers of Ten." Working on one topic per week, the students are required to place five dated items of information and a related graphic about their specific project location into each of these short timelines, totaling about fifteen entries per week. This information comes from the lectures, required readings, and their own research. The final project for the semester is for small groups of students working on locations in close proximity to create an oversize graphic timeline where their multiple topical timelines are collated and accurately juxtaposed to show concurrent events and to describe and illustrate changes in the natural environments of their group region from the deep past to the present.

The Excel spreadsheet timeline exercise is working out very well. Students seem to enjoy the preliminary class activities that focus on active placement of images and data in temporal sequences prior to data entry in their individual spreadsheets. Many resources are used for these activities, such as: global, continental, and regional maps from Ron Blakey's Library of Paleogeography; global climate history maps from Chris Scotese's Paleomap Project; individual frames from the Visible Paleo-Earth (VPE) project; screen shots from model animations such as retreat of Laurentide Ice Sheet from CSDMS; cropped sections of temperature graphs from Global Warming Art; species maps from the NOAA Pollen Viewer; repeat photos of glacial retreats in National Parks; Storm Event descriptions and dendrochronology data downloaded from the NCDC databases; screen shots from historical animations of land use and cover changes; cropped sections of dated phylogenetic diagrams for various species; and much more. For their own timeline entries, students are required to interpret the graphic images and related materials in order to describe relevant events taking place near their location at any given time.

Each class activity looks something like the card, photo, etc. placement procedure that curatorial intern Leá Norcross used to build a timeline of space exploration at the Colorado Springs Fine Arts Center (shown at http://blog.csfineartscenter.org/2009/12/building-timeline-of-space-exploration.html).

The North American Environments class activities are, of course, all much busier, with more students participating, but each separate activity is more tightly focused on a closely related set of concepts such as plate tectonics, orogenies, and sea level changes.

So far, I have been focusing only on relative placement along a timeline with a few key anchor points such as beginning and end dates for the Cenozoic, Mesozoic, Paleozoic, and Precambrian.

My next step will be to try for more accurate temporal placement along a measured and color-coded timeline ribbon. In a Homeschool Den activity (shown at http://thehomeschoolden.blogspot.com/2010/08/geologic-time-line-activity.html), the following colors, measurements, and rationales are paraphrased as:

• Hadean, red, 9ft 4 inches (flaming gasses, volcanoes, etc.)
• Archaean, sage green, 17 feet 4 inches (great rains, poisonous oceans)
• Proterozoic, yellow, 26 feet (cyanobacteria and the sun worked together to put oxygen into the atmosphere)
• Paleozoic, blue, 3 feet 9 inches (most life lived in the seas to protect it from harmful rays of the sun)
• Mesozoic, gold, 2 feet 5 inches (great reptiles, among other life)
• Cenozoic, green, 10 inches (plants, animals, birds, humans)

Initially, I was somewhat reluctant to use such activities in a university course. They seemed much too juvenile. The course feedback indicated that the students did not think so, and that they wanted more of these kinds of activities. Some of them are planning to become teachers and see how they could use simplified versions of the activities with young children. Others acknowledge they probably will have some, if less directed, contact with children, their own, in their extended family, or in their community, and they will need to explain a few key environmental and temporal concepts in clear and simple ways.

In fact, this focus has become a central theme in the course. It provides a purpose for the final group regional project of an oversize graphic timeline. It is a "commissioned" work which will be placed in a local school, museum, or nature center. The Excel Timeline and the Portfolio of lecture notes, reading summaries, etc. become the official reference manual for the use of local teachers, docents, or rangers who will use the graphic timeline for teaching or interpretation. My students this semester are very excited that I will be getting a chance to walk the real Trail of Time along the edge of the Grand Canyon, which is, in fact, the focus of one student's project.

The Colorado Plateau in general is a popular choice for these projects, so I hope to learn a lot more about both natural and anthropogenic changes over time in the region at this workshop. In addition, I hope to learn more about ways of assessing my students' understanding of temporal concepts, and to gather some ideas about how to deal with more sophisticated concepts such as rates of change. In particular, students seem to find it especially hard to understand the rates at which different geomorphological features form over time, but there hardly seem to be any properly dated animations or other temporal visualizations to help overcome this barrier.

Acknowledgements:

With many thanks to the FGCU students in EVR 4930 North American Environments in Spring 2012, whose work is shown in the images in this essay.