Bacteria of 230 million years ago found preserved

January 08, 1993|By Knight-Ridder News Service

BERKELEY, Calif. -- Scientists have found the oldest intact land organisms known -- microscopic creatures trapped in amber for 230 million years and so remarkably preserved that one was caught in the act of consuming another.

Scientists say the discovery offers a unique and vivid snapshot of life in the dawn of the dinosaur age.

With any luck, scientists say, they eventually may extract DNA from these tiny creatures, which are surprisingly similar to those living today. They include single-celled protozoans, bacteria, branches of algae and spores that may have come from a fungus.

"What we have here are the actual bodies of these organisms," says George O. Poinar Jr., an expert in ancient life forms from the University of California, Berkeley, whose report on the find appears today in the journal Science.

One oval creature appears to be eating a strand of blue-green algae, Mr. Poinar says. And a small grain of pollen was trapped as it started to sprout.

The amber probably formed a quarter of a billion years ago in the crook of a tree, Mr. Poinar says. A lively microscopic community lived in the water trapped by this crook and, as the puddle dried, it was covered by sticky sap that also snagged windblown spores and pollen.

Discovered near the German Alps by a collector, the amber was crushed and examined through a microscope by Mr. Poinar and graduate student Benjamin M. Waggoner.

Ancient fossils are not uncommon. Traces of microscopic organisms have been found dating almost to the beginning of life on Earth, some 3.5 billion years ago.

But they rarely contain much material from the original organism. And virtually all fossils of creatures that lack shells or bones are found at the bottom of former oceans or lakes, protected by layers of mud.

Amber is almost the only means of preserving these soft organisms on land.

Before the latest discovery, the oldest fossils identified in amber dated back only 130 million years.

"These are really quite extraordinary deposits," says Robert G. Douglas, dean of natural sciences at the University of Southern California. "You just don't see those kinds of organisms preserved in the fossil record; these are very delicate. To be able to actually see them in three-dimensional form is quite extraordinary."

Jere Lipps, a paleontologist at UC-Berkeley, says, "Amber preserves an environment that is almost never preserved in any other way, so it's kind of exciting. George Poinar has found all kinds of things in amber, from lizards and frogs to trees and leaves and mushrooms. He just keeps looking at stuff and finding all kinds of amazing things."

In September, Mr. Poinar's team and another one from New York separately announced they had been able to extract bits of the genetic material DNA from insects entombed in amber for 40 million years.

But today's techniques are not delicate enough to pry DNA from single fossilized cells for genetic studies, Mr. Poinar says.

Nevertheless, he says, the discovery confirms something scientists had long suspected about evolution.

"We have this idea, which tends to be supported here, that the smaller the forms of life, the longer they survive," Mr. Poinar says.

zTC Similarity of the microbes to modern families, he says, "means they had already gotten everything together a quarter of a billion years ago" and just carried on from there.

Baltimore Sun Articles
|
|
|
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.