Prehistoric Leaves and Climate Change

Teaching Climate Change through Prehistoric Leaves

Leaf 5

Leaves Tell the Story of Climate Change

In a previous post I provided a list of climate change resources for those interested in knowing more about climate change, and for those who may be needing resources for teaching about it. In today's post I want to share with you another great resource.

One of my favorite types of lessons, in and out of the classroom, involves real world applied science, which integrates fields that might once have seemed diametrically opposed. The folks in Smithsonian Education have created a wonderful lesson plan all about the research of Scott Wing, an SI paleontologist, whose work focuses on paleobotany, climate change, and leaf-margin analysis of fossil leaves from about 55 million years ago. This is a free curriculum, complete with lessons and background materials, that can be found online. It's aimed at middle school students, though it could be adapted for high school.

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An example of one of the leaves used in the activity of the lesson (Photo: Smithsonian).

Wing's work focuses in studying the early Cenozoic age, in Wyoming's Bighorn Basin.  Scientists had once speculated that during the early Cenozoic Era climate change had occurred, something called the Paleocene-Eocene Thermal Maximum (PETM), which had to do with the release of carbon dioxide into the atmosphere, possibly from volcanos or an asteroid.  While mammals can move around (and they have the ability to thermoregulate) and change locations, plants can't. The types of plants you find, and their shapes, can give a clue to what was happening with the climate. As you know, some plants do well in very warm climates and some do not. Those that live in warmer environments may have more serrated or toothed leaves, to allow them to take in CO2 more easily, while those in cooler environments may be more smooth leaved for conserving resources and energy.

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Another type of leaf used in the lesson activity (Photo: Smithsonian).

The information that Wing is gathering about climate change in the early Cenozoic Age, is thought to show similarly  what is happening currently with the addition of carbon in the present day. By studying these ancient leaves and modeling what happened in the past, students can get a glimpse into what might happen in the future.

Here is a video from the site explaining Wing's work.

This lesson has students compare fossil leaves from two different time periods in the Cenozoic Age, just before the PETM (55.85 mya) and during its height (55.75 mya). There is plenty of math, because students must calculate prehistoric temperatures by using a formula based on percentages of leaf margins and using Celcius or converting to Fahrenheit. You can download the free PDF of curriculum, and leaf images on SI's website. There is also a leaf sorting activity and interactive online options, but I could never get it to work on any of the browsers I used.  I found the paper activity and lesson was just fine though.

This is a fun resource and a neat read for those who might be interested in climate change and learning from the past. If you need to take this unit up a notch, try adding in content about plant anatomy and physiology, or even evaporation and transpiration.

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A fossil leaf used in the lesson (Photo: Smithsonian).