Teach the Earth > Sedimentary Geology > Sedimentology, Geomorphology, and Paleontology 2014 > Teaching Activities > Landscape Evolution Debate

Landscape Evolution Debate

Amanda Schmidt, Oberlin College
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This page first made public: May 27, 2014

Summary

Students are assigned to read one of the three papers on tectonic geomorphology (landscape evolution) published by Nature in 2003 (Burbank et al., Dadson et al., and Reiners et al.). All also read the editorial by Molnar from the same issue. They work with others who read the same paper to understand the paper and then jigsaw into new groups to discuss the similarities and differences between the papers and to see if they can come to any conclusions about major drivers on landscape evolution. This activity has them work on multiple levels of Blooms Taxonomy - they read and understand a paper, analyze the results of the paper, and then evaluate the paper in the context of two other papers presented by peers.

Context

Audience

This is used towards the end of the semester in a required undergraduate course on geomorphology. There is a page describing this class here. The only pre-requisite for the class is Physical Geology, so it has students ranging from first to fourth year in it. To be honest, I think this activity works a bit better with the older students than younger, but the younger ones are often quite good students and do fine. In addition, anyone who has reached the end of a geomorphology or surface processes class where they are talking about landscape evolution has probably developed enough intellectual context to read these papers. They really need to have read papers before, though, or else they won't be able to make the jump to both understand AND evaluate a paper in one go.

Skills and concepts that students must have mastered

Students should have some experience reading primary literature (not a ton, but at least some) and have some idea of the basic organization of papers and how to read a paper from the literature. It is not necessary that they have previously gone beyond simply reading papers for comprehension, though of course any prior experience evaluating papers will help them to evaluate these. They should have learned a bit about landscape evolution and feedbacks between climate, tectonics, and erosion. They need to be comfortable with basic erosion processes.

How the activity is situated in the course

This is a stand alone exercise in the week on landscape evolution. It takes place in one 80 min class with students reading a paper before class.

Goals

Content/concepts goals for this activity

  • Processes driving erosion in different locations

Higher order thinking skills goals for this activity

  • Limitations to primary literature (analyzing literature)
  • Thinking about the regional context of work and whether it can be extended to other locations
  • How to reconcile seemingly disparate results (evaluating literature)
  • How much can you interpret from a given data set (analyzing and evaluating data)

Other skills goals for this activity

  • Working in groups to discuss the papers and try to understand them
  • Analyzing and evaluating primary literature

Description and Teaching Materials

Students are assigned to read the Molnar editorial and one of the three papers from Nature in 2003 (Burbank et al., Dadson et al., and Reiners et al.) before class. I start out with a brief introduction to how the class is going to work (about 5 minutes).

For the first part of class (approximately 25 minutes), they work with others who read the same paper to understand the paper. What are the aims of the paper, what were their methods, what data did they collect, what are the results, how do they interpret the results? I go around and answer questions from each group and help them to stay on target with their discussions. This part is really focused on analyzing a paper and evaluating it in the context of their knowledge of geomorphology after nearly a semester studying it.

After 25 minutes or so I have all the groups count off so that there will be new groups of 3 (one person is an expert on each paper) and groups shuffle to form new groups. In the new groups, each student presents his/her paper (the one they read) and answers questions from the group. After all students have done this (about another 20-25 minutes), they have a discussion on the similarities and differences between the papers. What can they draw from each paper? How is each paper limited? Are there any overarching conclusions they can draw about landscape evolution? This part of the activity is focused on evaluating papers in the context of other material in the literature. (This takes about 10-15 minutes).

As discussion is winding down, I have the class come back together for a final discussion. Groups report on what they talked about and I give them some context of more modern work that has been done. I use Henck et al. 2011 for some context of one way to reconcile the papers, but any number of more recent papers would work. That is just the one I happen to use (disclaimer: I wrote the paper, it just came out right around the time I changed my name). I don't have them read it - I just explain it to them.

This could easily include a writing assignment by having groups write abstracts for the papers they read and by having them do a reflection paper after class.

Burbank, D. W., Blythe, A. E., Putkonen, J., Pratt-Sitaula, B., Gabet, E., Oskin, M., Barros, A., and Ojha, T. P., 2003, Decoupling of erosion and precipitation in the Himalayas: Nature, v. 426, no. 6967, p. 652-655.

Dadson, S. J., Hovius, N., Chen, H., Dade, W. B., Hsieh, M. L., Willet, S. D., Hu, J. C., Horng, M. J., Chen, M. C., Stark, C. P., Lague, D., and Lin, J. C., 2003, Links between erosion, runoff variability and seismicity in the Taiwan orogen: Nature, v. 426, no. 11 December 2003, p. 648-651.

Henck, A., Huntington, K. W., Stone, J. O., Montgomery, D. R., and Hallet, B., 2011, Spatial controls on erosion in the Three Rivers Region, southwest China: Earth and Planetary Science Letters, v. 303, p. 71-83.

Molnar, P., 2003, Nature, nurture and landscape: Nature, v. 426, no. 11 December 2003, p. 612-614.

Reiners, P. W., Ehlers, T. A., Mitchell, S. G., and Montgomery, D. R., 2003, Coupled spatial variations in precipitation and long-term erosion rates across the Washington Cascades: Nature, v. 426, no. 6967, p. 645-647.

Teaching Notes and Tips

Due to copyright reasons I cannot upload the papers referenced in this activity. Please contact me if you do not have access to them through your school library.

A few comments on dealing with range of students in the class: This is a persistent problem over the course of the entire semester. I have students that range from taking their second geology class in college to those who have taken every class that we offer. I try to encourage the more senior students to work with the younger ones so that they are gaining skills by explaining information to younger students rather than getting irritated that the class is moving slowly. There are times that it is unavoidable, but I do try to spread the seniors out. In activities such as this one, where I assign who reads which paper, I make a point of spreading out the seniors. It's harder to make that work for the second groups, but I think with careful planning, you probably could.

In terms of guiding students in their discussion of the papers, I do this a bit in the introduction to the activity. The students in my class also have read ~6 papers from the literature on geomorphology by the time they get to this activity. This helps enormously as it means that students already have some context for how to read and understand papers in the scientific literature. They also write full lab reports (3/student/semester) and in setting up the rubric for grading lab reports, we have already gone over what types of information go into each part of a paper. If your students don't have this background, I think it is important to discuss with them how papers are organized, what goes into each section, and how Nature papers are a bit different from other papers. Talking with students about papers telling stories may help as well.

Common misconceptions/stumbling blocks students have and how to address them:

  • Where the methods are in Nature papers. This is probably best addressed in the introduction to the activity or else you will be explaining it to every group over and over again.
  • What the different time scales are for different pieces of data. This isn't really a misconception as much as something to watch out for with students. They don't always realize that the different types of data don't happen over the same period of time. I find it helpful to have them think about what the different timescales mean.
  • Students often don't critically evaluate the claim in each of the papers that what they learn is universally true. This is probably the biggest misconception that comes out of the assignment. So helping students to think critically about the geologic context for each paper helps them to feel less like they are irreconcilable.
  • Students have trouble reading the topographic profile figures. Going over these at the beginning of class could be helpful.
  • Students have trouble getting deeper and thinking that the authors may not automatically be correct. This is similar to another point, but it's more about whether the conclusions they draw from the data are even something the students agree with.
  • Given the different timescales that climate (modern precipitation), tectonics, and erosion happen over, it's helpful to do some conceptual model discussions with students about feedbacks between these terms. So how could precipitation drive erosion? What about tectonics? How can tectonics drive climate (modern precip)? What about erosion? How can erosion drive climate and tectonics? Under what circumstances is one arrow/direction more important than others? I think this helps them to evaluate the papers a bit better.

Assessment

I use a formative assessment of student discussion quality. Specific questions to consider with the formative assessment are outlined below, organized by first round (all have read the paper) and second round (with people who have not read the paper).

First round - when students are discussing with others who have read the same paper:

  • Do students understand the question being asked/hypothesis being tested in the paper? Here I am looking for simple re-casting of the main goals of the study. If not, ask them leading questions to get them to think about the goals of the paper they read.
  • Do they understand the methods and type of data being presented in the paper? Here I am looking for a quick summary of the methods/results. If not, ask them leading questions to help them to get this information from the paper. Sometimes they have trouble with this if they don't look at color versions of the figures, so it helps to have a color printout. They also have problems with the organization of Nature papers - methods at the end - so talking them through that can help too.
  • Do they understand the conclusions being drawn? Here I am looking for knowledge of the paper. As above, I ask leading questions to get them there if they don't. I also answer their questions.
  • Can they identify any limitations for the paper? Here is where the leading questions can be really helpful. Helping them to think about geographic/spatial limits of the study (they are all very spatially specific), technique limits (such as distribution of samples or time scale of comparisons), and whether the conclusions agree with what they see in the figures. This section takes a bit of mentoring for groups with younger students who have taken fewer geology classes. With this point, I am looking for students to understand the paper well enough to evaluate it, rather than just summarize it. If they need help getting there, I try to help them.

Second round - when students are presenting their paper to peers who haven't read it. This part gives me more information about how well specific students understood what they read:

  • Does the presenting student articulate clearly the goals, methods, results, and conclusions of the paper they read?
  • What is the quality of the questions asked by the students? Are they at the level of summarizing or are they evaluating?

In the case of my class, the feedback the students get is me answering questions, asking them questions, and verbally telling them that I agree with what they are saying. Their participation becomes part of their participation grade for the course.

All of these bullet points could be used in a writing assignment. Students could write abstracts for the paper they read and could write a response paper evaluating the arguments in the three papers after the discussion.

References and Resources

Here are full citations for all papers mentioned:

Burbank, D. W., Blythe, A. E., Putkonen, J., Pratt-Sitaula, B., Gabet, E., Oskin, M., Barros, A., and Ojha, T. P., 2003, Decoupling of erosion and precipitation in the Himalayas: Nature, v. 426, no. 6967, p. 652-655.

Dadson, S. J., Hovius, N., Chen, H., Dade, W. B., Hsieh, M. L., Willet, S. D., Hu, J. C., Horng, M. J., Chen, M. C., Stark, C. P., Lague, D., and Lin, J. C., 2003, Links between erosion, runoff variability and seismicity in the Taiwan orogen: Nature, v. 426, no. 11 December 2003, p. 648-651.

Henck, A., Huntington, K. W., Stone, J. O., Montgomery, D. R., and Hallet, B., 2011, Spatial controls on erosion in the Three Rivers Region, southwest China: Earth and Planetary Science Letters, v. 303, p. 71-83.

Molnar, P., 2003, Nature, nurture and landscape: Nature, v. 426, no. 11 December 2003, p. 612-614.

Reiners, P. W., Ehlers, T. A., Mitchell, S. G., and Montgomery, D. R., 2003, Coupled spatial variations in precipitation and long-term erosion rates across the Washington Cascades: Nature, v. 426, no. 6967, p. 645-647.
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