In his spare time, Steve Sullivan, the urban ecology curator at the Chicago Academy of Sciences, likes to hunt squirrels. Recently, he showed a specimen he was planning to cook up and serve as dinner to a friend.

"That's not dinner!" Sullivan's friend exclaimed after inspecting what appeared to be a rather meager hunk of meat.

And yet, as Sullivan points out, 60 or 70 years ago, an ordinary American family could make a similarly sized hunk of meat last for an entire week.

"Food: The Nature of Eating," the new exhibit Sullivan helped curate at the Peggy Notebaert Nature Museum (it opens tomorrow and will stay open till 9/8), examines, among other things, how the changes Americans made to nature affected their diets and how they think about food.

"We tend to think that there's a human world and a natural world," says Sullivan, "but we're part of the natural world, and we're most connected to it through our food."

The first part of the exhibit takes you back to the early 1800s, when Chicago was entirely covered by prairie. Initially, settlers believed the prairie was a vast wasteland, so infertile that it couldn't support real trees, only grass. This impression was only reinforced by the discovery that the grass grew out of a layer of sod so thick that it was, in Sullivan's words, "bulletproof."

And then John Deere invented the plow and suddenly farmers were able to slice through the layer of sod to the rich soil below. (A couple of plows are on display. One—a replica—is set up so you can simulate, on carpet, the experience of cutting sod yourself. You realize: that shit ain't easy.) Magically, it seemed, the midwest became the so-called "breadbasket of the world," with endless fields of corn and wheat and soybeans. There was food for everyone, and even a surplus to feed more livestock, which meant, of course, more meat.

But as Sullivan points out, there weren't only benefits to the advent of the plow—there were costs as well, most notably the lives of animals. The Eskimo curlew and the passenger pigeon both became extinct. The prairie chicken, the most charismatic of little birds, nearly met the same fate. The black bear, once the most important source of food for Illinois settlers, was driven off to the mountains. ("It's in the mountains because we're not in the mountains," Sullivan explains. "Does any animal really want to live in the mountains?") And the bison, once the stereotypical food of prairie dwellers, vanished too.

The exhibit features a taxidermied Eskimo curlew and prairie chicken as well as a large and rather impressive bison, all part of the Academy of Science's collection; unlike a lot of museum exhibits in recent years, this one was entirely self-curated. The bison spends most of its time in cold storage to keep pests from growing in or on it and was transported to the museum in a large refrigerated trailer. It's huge. You could imagine an entire family subsisting on that for a week.

The idea of cost-benefit persists through the exhibit. We have nitrogen fertilizer now instead of animal waste, and we use it to grow more food than ever before, all the while using less land. (The exhibit contrasts a model of a children's-book-style farm with pictures of an actual industrial farm. It's sure to disappoint any child who looks at it.) Which seems like an unequivocal benefit. And yet . . .

"We could use the land for wildlife," Sullivan says, "but there's the temptation to grow more corn to feed to cows, which will let us have bigger hunks of meat." He pauses for a moment. "This exhibit is not an advocate. It's meant to empower viewers to know the effects of their decisions. Our ancestors lived well on less meat. We live well on more meat."

However, as the section of the exhibit about food miles shows, most of us don't really don't think much about food at all. Which is why we eat salmon that travels 10,000 miles from Alaska, where it's fished, to China, where it's deboned and gutted, and finally back here to be eaten—even though a direct flight is a mere 3,000 miles. The problem with the 7,000-mile difference isn't just about space and time. It's also about fuel consumption and production of greenhouse gases.

Why can't we fillet our own damned salmon?, Sullivan wonders, and then use the bones for stock and the skin to feed our cats, the way our grandparents did?

"Consumers have the opportunity the influence the market," he says. And, indeed, the exhibit presents several alternatives to commercially grown and produced food: urban farms, rooftop farms, and organic farms.

But instead consumers eat hard, flavorless, pink-tinged winter tomatoes that travel 2,000 miles from South America.

"That's why we've been working with the Green City Market," Sullivan says. "We want to help people develop their palates to know how a tomato should taste. We as an institution are an urban gateway to nature and science. Science should inform how we interact with nature through food."

Throughout the exhibit, the curators have placed photos and brief narratives of how various Chicagoans past and present have found and prepared their food, ranging from a prairie-dwelling family in the 1850s to Iliana Regan, the owner-chef-forager of Elizabeth. There are models of the gates of the old Union Stockyards, an old-school Dominick's grocery store, and a typical Chicago apartment dining area (complete with radiator) where the plates are touch screens and you can flick through pictures of various meals with provocative questions about where the ingredients came from, how they were assembled, and how this relates to your own personal eating habits.

There's also a rabbit that Sullivan killed and mounted himself. It's about the size of the rabbits you sometimes see hopping through local yards. It served as dinner for a family of five.