For now, at least, the textbooks indicate life on Earth originated 3.5 billion years ago. Michael Parrish, chair of NIU’s Department of Biological Sciences and a noted paleontologist whose mammal and dinosaur discoveries are helping rewrite the history of Earth’s inhabitants, sees remnants of ancient life all around us.

“The real window to the ancient past is single-cell algae or fungi,” Parrish says. “Those are very diverse groups today, but in terms of their level of complexity, they are similar to organisms that first appeared on Earth.”

Similarly, sturgeons and jawless lampreys are like the early spineless fish that swam the waters of prehistoric Earth 500 million years ago, while lung fish today display features that make apparent the bridge between water and land creatures. In salamanders, Parrish sees the slithery resemblance to early terrestrial vertebrates, and in crocodiles, turtles, and especially birds, he glimpses the shadow of the dinosaur.

“There’s pretty much a consensus that there is a very diverse group of dinosaurs that are still around today—they’re just birds,” Parrish says. “We now have evidence of dinosaurs that, while they weren’t birds, had feathers. Separately, there’s one particular group of small meat-eating dinosaurs that developed the ability to fly. In any part of the bird’s skeleton, you see pretty much a direct comparison to dinosaurs, except modern birds don’t have teeth.”

Of course, Parrish has more than glimpsed the past. In 1999, he was among the scientists who announced the fossil discovery of a mouse-size mammal that lived in Madagascar 165 million years ago. The fossil represents the oldest known modern mammal. He also was part of a team that discovered the oldest known dinosaur fossils, again in Madagascar. The jawbones of the two prosauropods—ostrich-size plant-eaters with small heads and long necks— date to about 230 million years. In yet another study, Parrish and a colleague used computer modeling to determine the neck movement of the long-necked sauropods, the giants of the dinosaur world.

The ability to analyze huge amounts of data have made it possible to do everything from computing family trees of organisms based on DNA sequences to computerized modeling of skeletal structures, Parrish says. With major discoveries being announced regularly, paleontologists are filling in large gaps in the planet’s life history.

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