Image for post
Image for post
Palmisano Park, Chicago. Original quarry high wall in background.

I recently participated in a workshop on America’s Geoheritage. What is geoheritage? One definition is that this an area with geologic features with “significant scientific, educational, cultural, and/or aesthetic value.[i]” One form of geoheritage sites is: “places where geologic features or landscapes played a role in cultural or historical events”. Although there is an unofficial list of geoheritage sites maintained by the National Park Service[ii], the naming of such sites is still in its infancy (thus the workshop). Many locations in Chicago and the surrounding region are prime candidates for eventual designation as culturally and historically significant geoheritage sites. …


Image for post
Image for post
My Great grandmothers brass candlesticks

At the beginning of the Jewish New Year last week I lit candles to mark the day. The candlesticks I used were my maternal great grandmothers, brought with her to America in 1910. These were passed to my grandmother, then to my mother, and finally to me and my family. Staring at the candles connected me to an ancestor I had never met; I only know of her from a single photograph and the stories my grandmother and mother told. Of my other great grandparents, I know even less, just names and photos. But I am connected to them also…


Image for post
Image for post
Earth’s climate has gradually cooled for the last 50 million years, culminating in Northern Hemisphere ice ages where ice sheets periodically advance and retreat. The ice last began to rapidly retreat about 18,000 years ago. Based on current greenhouse gas emissions, global temperatures over the next century and beyond will reach levels not reached for millions of years. CREDIT Thomas Westerhold. Ref: Westerhold, T., et al. 2020. An astronomically dated record of Earth’s climate and its predictability over the last 66 million years. Science 369(6509):1383–1387.

It’ll start getting cooler. You just watch,” — President Trump

“I wish science agreed with you,” — California official.

“I don’t think science knows, actually,”- President Trump.

It’s nice to know that President Trump understands Milankovitch cycles. In 1976 it was conclusively demonstrated that the multiple advances and retreats of the Northern Hemisphere ice sheets over the last 2.5 million years are controlled by small periodic changes in the Earth’s orbit[i], a hypothesis put forth decades earlier by Milutin Milanković. Over roughly the last one million years, the ice has grown and retreated on a cycle of about 100,000 years…


In 1986, Paul Simon sang of the “Boy in the Bubble.” The real boy in the bubble, David Vetter, suffered from severe combined immunodeficiency (SCID) and lacked immunity to infection. He lived in sterile enclosures until he died in 1984 at the age of twelve, following an unsuccessful attempt to cure him.

We all live in different bubbles, designed to keep harm out. Some of these, like family, we are consciously aware of. Others are hidden from us until outside incidents or individuals make us aware of them. In some cases, we may even reject the idea that they exist…


“Is there anybody out there?” — Pink Floyd

Sometimes technology takes a long time to develop. One of my childhood memories is seeing the AT&T Picturephone at the 1964 World’s Fair in New York. The technology was also featured in the 1968 film 2001, where a video call was made from a space station. This early promise was never delivered on; almost no one in the late twentieth century had a Picturephone. Now a half-a-century later, being able to see who we are talking to has become a given. Whether it is Zoom, Skype, Facetime, or Google Hangouts, and no…


Image for post
Image for post
Spectators at the Gondwana vs. Laurentia soccer game at the 2012 quadrennial international ICHNIA meeting in Newfoundland. Such events help build relationships among researchers from diverse backgrounds.

As most of us shelter in place, many voices have suggested that this is an excellent to time to reflect on and perhaps reform some basic aspects of society, such as the pay of “essential workers” or universal health care. The scientific enterprise is no exception; in particular, the pandemic has hastened an already ongoing movement to rethink a cornerstone of the enterprise, the scientific conference. As I wrote last time, the recent International Association for Landscape Ecology — North America chapter meeting I attended was transformed in an astonishing five weeks from a traditional in-person meeting to fully online…


I have been attending scientific conferences of various kinds over my entire career. Some things have changed over the decades; most notably (and thankfully) PowerPoint has replaced 35 mm slides. But the overall structure has not changed. There are short talks, generally fifteen minutes long, presented consecutively from a podium and illustrated by slides. Often there are competing sessions organized around specific themes. There are sometimes plenary talks, where a distinguished member of the profession speaks at length on a topic of general interest. Accompanying the oral presentations are poster sessions, where anxious presenters, often students, will stand in front…


Image for post
Image for post
A forest fire model generated using NetLogo https://ccl.northwestern.edu/netlogo/

A number of years ago, my explorations into fractals led me to the amazing concepts of percolation theory and how they could be used as a heuristic tool to explore a whole range of phenomena. The basic concept of percolation theory is easy to explain, using the “forest fire” model. Imagine a square grid, some 100 cells on each side. Now randomly plant a tree somewhere in the grid. Plant another and another until about 10% of the grid cells have a tree on them. Next, send down a lighting bolt down onto the grid. If it hits a tree…


Image for post
Image for post
A caddisfly case from the Oligocene of Montana. The case is made of tiny ostracode shells.

In a Peanuts comic that had a place of honor on my dorm door, Peppermint Patty is taking an exam and is asked to: “Explain World War II.” Patty incredulously responds: “Explain World War II !?” The last panel, further explains: “Use both sides of the paper, if necessary.” I recently had a similar reaction, when science reporters, interviewing me about my most recent paper, asked me to explain in a few words, “when do bones and teeth become fossils?” Although they are orders of magnitude fewer in number than those written about World War II, nevertheless there are many…


Image for post
Image for post
In some Chicago neighborhoods, you can still see where the sidewalks were raised.

About 20,000 years ago, where I am sitting in Chicago was covered by about a kilometer of ice. This was the height of the most recent advance of ice sheets in the Northern Hemisphere, which had begun some 80,000 years earlier. About 15,000 years ago the ice sheets began to retreat and within the next 5000 years they had totally disappeared. These great ice sheets left an indelible mark on the landscape, the most notable being Lake Michigan and the other Great Lakes, carved by the glaciers in the underlying bedrock. Paralleling the current shore of Lake Michigan to the…

Roy Plotnick

Paleontologist, geologist, ecologist, educator. Professor at the University of Illinois at Chicago. Website:https://sites.google.com/uic.edu/plotnick/

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store