Digging into the 'deep history' of life

(CNN) -- Unlike most budding paleontologists, Andrew Knoll's fascination with fossils didn't lead him to dinosaurs. Instead, he focused on the first stirrings of life -- the evolution of prehistoric bacteria.

"There are times when I wake up and wish I could find something as sexy as a dinosaur," Knoll admitted. "On the other hand, what I'm trying to find out is how the modern fabric of the world came to be and what was in place long before the dinosaurs existed."

Sure, a brontosaurus is big, but a bacterium is better, according to Knoll.

"Bacteria forms the ecological microcircuitry of the Earth," he said. "All of the great cycles of elements that sustain biology on this planet -- the carbon cycle, cycles of sulfur and nitrogen and phosphorous -- have links in that circuitry. The world would do just fine in terms of the persistence of life without plants and animals, but if there were no bacteria, life on Earth would stop in an instant."

The Harvard University researcher specializes in what he calls the "deep history" of life, going far beyond the unfolding of animal diversity 550 million years ago known as the "Cambrian explosion."

"The evolutionary process really began with the origin of life, perhaps 4 billion years ago, and then continued with organisms whose size and shape and complexity was similar to what we would recognize as bacteria today," he explained.

"Over long periods of time, more complex cells arose. They then formed multicellular consortia that ultimately became functioning animals with tissues. We, along with everything else that's alive today, are the product of this 4 billion years of evolutionary history."

More stories of these earliest life forms are embedded in rocks and geological outcroppings, waiting discovery by scientists with the skill and patience to interpret them, Knoll said.

"I find that just intoxicating," he added.

Many people, however, are more thrilled by "Jurassic Park III." It's unlikely that the subject of Knoll's work ever will have a featured role in a Steven Spielberg project.

"Bacteria just needs a better publicist," he said.