From Plant Press, Vol. 22, No. 1, January 2019.
By Pamela Tuchscherer
Retired teacher and Department of Invertebrate Zoology volunteer Pamela Tuchscherer explores her experiences attending the Smithsonian Botanical Symposium, “Plants in the Past: Fossils and the Future,” which convened at the National Museum of Natural History in May 2018. She also gives us a first look of the new David H. Koch Hall of Fossils – Deep Time, which is scheduled to open to the public on June 8, 2019.
“A person would have to take themselves out of the human context to begin to think in terms of geologic time. They would have to think like a rock.” - Terry Falke, photographer
It’s hard to grasp the concept of deep time. I reflected on this geologic period as I studied a fossil illustration in the rare book, Antediluvian Phytology. The plant fossil was 55 million years old. What could I use as time markers in that distant past? It was after the dinosaurs roamed the earth, but before humans existed. Imagine what Edmund T. Artis, 1800s fossil collector and author of the book, thought when he collected the Carboniferous plant fossil fragment. He tried to envision it as a whole organism even though it had little in common with existing plants. Back then, geologic time before humans was a controversial concept even to some scientists.
I examined Artis’ publication, and other rare books highlighting fossil plants, at the Joseph F. Cullman 3rd Library of Natural History. Having entered through locked doors, I had entered one of the two most secure locations in the museum. (The other being the gem vault). The library, containing 10,000 anthropology and natural science rare books, is used by scientists and researchers working on taxonomy and classification of species. I viewed the books on display during a behind-the-scenes tour offered during the Smithsonian Botanical Symposium, “Plants in the Past: Fossils and the Future,” where I was introduced not only to unique extinct plant species, but also to the origins of some of today’s plant diversity.
Kirk Johnson, Director of the Museum of Natural History and a paleontologist himself, gave the opening remarks at the Symposium and noted that the discussion of ancient plant fossils coincides with the development of the Natural History Museum’s Deep Time exhibit. A goal of the exhibit is to show the public that paleontology is relevant to modern life. It will demonstrate how ancient plant and animal fossils are key to understanding the interaction of earth and life systems with more than 30,000 ft2 of new fossil displays.
Jonathan Wilson, paleobotanist at Haverford College, and a speaker at the Symposium raised the question, “How can we better estimate the way climate change will impact today’s ecosystems?” Plant fossils, he explained, are key sources of environmental information because their wood structure, as well as leaf shape and size, record and respond to environmental changes in a predictable biophysical way.
Vegetation and climate influence each other. This is referred to vegetation-climate feedback. “For example,” Wilson notes, “drought causes plant death and reduces the amount of carbon dioxide stored in plant tissues, thereby increasing atmospheric CO2 concentration and global temperatures."
Wilson used the rich archive of environmental evidence preserved in fossils to understand vegetation-climate feedback in deep time. He thinks it is critical to build an understanding of the whole extinct plants’ physiologies from root-to-stem-to-leaf, rather than trying to reconstruct them based on existing relatives. Extinct plants may not have functioned in ways known today. By comparing the physiology of these plants with today’s living plants strategies, it will help explain the adaptation of an organism to environmental changes over time. Wilson believes, “The history of plant life holds important clues about the planet’s future.”
Scott Wing, Smithsonian curator of fossil plants, has discovered that fossil plant records show evidence for the triggers and effects of global warming. He has studied plant fossils that reveal the intense global warming that occurred 55 million years ago during a period labeled PETM (Paleocene-Eocene Thermal Maximum). In addition to high temperatures, high levels of carbon in the atmosphere were evident. This period is widely recognized as “the best geological analog for the human-induced global warming that is happening now.”
The new Deep Time exhibit, opening in June 2019, will make comparisons between events in the history of life and our current alterations of Earth systems. Wing points out, “We’ve changed the composition of the atmosphere, changed the climate and the chemistry of the ocean. There is no ecosystem that doesn’t have human fingerprints. We are now as powerful as geological forces were in the past. Things that we do now will echo forward into the future.”
Fossils of pollen grains and leaves will be featured in highlighted displays in the exhibit that will help visitors understand ecological change over time and emphasize the importance of plants in shaping this change. Fossil interactive programs and activities will provide hands-on experiences. In addition to describing current undesirable global changes, the exhibit will reveal practical solutions to global change including urban gardening and conservation programs.
Entering the exhibit, the public will start at the Earth’s creation, 4.6 billion years ago and end with their future. Visitors will walk through individual displays and observe changes over time. As they progress and travel through millions of years, they’ll discover how climate change and plant and animal interactions can transform the environment. There will be dinosaurs, but these extinct species will be shown in the context of their place in the ecosystem and their evolution through time. Plant fossils hold clues to both the past and the future and help scientist understand the results of the rapid biological change taking place today. “What few realize,” Wing notes, “is that this rise in CO2, and the heat wave it will cause, will persist for thousands or tens of thousands of years.” The hope is that visitors will gain a larger sense of the legacy they leave behind as well as the one they have inherited.
Comments