He says that when it comes to extinctions in specific locales, a close look at the sedimentary architecture often suggests a different interpretation.
"When we go to some place where there seemed to be a mass extinction and look in real detail at one stratigraphic section, we see all these environmental changes and we see that there are taxa present and then they go away," he says. "But because the environment was changing, we need to go somewhere else where that environment existed after this point in time to see if they're really gone."
Another situation ripe for misinterpretation occurs in places where a layer of sediment eroded for an extended time, followed by another long period of sedimentation. In such a case, the younger sediments (and dead organisms destined to become fossils) were deposited directly on top of much older sediments. Species living in the area may have evolved gradually during the entire time, but in the fossil record the changes will look abrupt.
"One could easily interpret this as being due to a short, intense interval of extinction and speciation, when what really happened was gradual change in species through time," says Patzkowsky, "but with the time gap, the gradual change is not seen."
Seeing the future in the past
In 2012, Patzkowsky and Holland distilled about 30 years of work by themselves and other scientists in the first book-length treatment of the field. The ideas they present in "Stratigraphic Paleobiology: Understanding the Distribution of Fossil Taxa in Time and Space" (University of Chicago Press) are beginning to make inroads in traditional paleobiology, says Patzkowsky, but there's still a ways to go.
"Part of the problem is that this blends sedimentary geology and paleobiology," he says. "Those are related fields and there should be a lot of cross-pollination between them, but it's really hard to pull them together. The fields have traditionally had different interests."
Still, he sees progress, especially among the next generation of scientists. In the summer of 2014, under the sponsorship of The Paleontological Society, he and Holland taught a field course on their methods for graduate students from around the country.
"There is a growing interest in understanding the ecology of ancient species, and how those species changed through time," he says. "One of the lessons that we learn from Earth history is the importance of environmental change and how that affects life. Looking at the fossil record is one of the few places we can really do that."
Questions about how ancient life forms responded to environmental change have taken on new urgency in recent years because of concern over human-generated changes to the planet. Levels of carbon dioxide now hover around 400 parts per million (preindustrial levels were under 300 ppm) and global temperatures are on the rise. Patzkowsky says ecologists can do in-depth studies of present-day habitats and organisms -- a mere snapshot in geological time -- and then try to predict what might happen to those organisms as their habitats change.
But there's another option, he says, because this is not the first time Earth and its residents have experienced similar conditions.
"The Pliocene [1.6 to 5 million years ago] was the last time that CO2 levels were at 400 parts per million. We're now moving into a Pliocene world, at least from the point of view of ppm CO2."
So what will happen to today's ecosystems and organisms as the climate warms?
"It's a question we can really get at in the fossil record," says Patzkowsky. Fossil organisms and the sediments they're embedded in can show us what actually did happen before, during, and after major environmental changes in the past.
"But if you're going to look at the fossil record," he says, "you need to look at the stratigraphic architecture first."
Mark Patzkowsky is professor of geosciences at Penn State. He can be reached at mep12@psu.edu.