Dec 13, 2006
Scientists have discovered a "microworld" of 220-million-year-old life trapped in tiny drops of ancient amber.
The fossilized plant resin preserved bacteria, fungi, algae, and microscopic animals known as protozoans some 220 million years ago—the era when the very first dinosaurs began to appear.
Surprisingly, these microscopic organisms look quite familiar to today's scientists.
Alexander Schmidt and colleagues from the Humboldt University of Berlin, Germany, report that the microbes have undergone few or no physical changes since the Triassic period—from 245 million to 208 million years ago.
(See an interactive feature on sea monsters of the Triassic (http://www7.nationalgeographic.com/ngm/0512/feature3/multimedia2.html).)
During Earth's many geological epochs and climatic shifts, countless species have appeared only to vanish or evolve. Yet these microbes appear to be related to present-day organisms.
The find was described in this week's edition of the journal Nature.
Most fossils of microorganisms have been found in marine sediments, not terrestrial environments.
And such marine fossils typically reveal patterns of great change over Earth's many epochs, unlike the new Triassic amber find.
"Many marine microorganisms serve as so-called index fossils [for the dating of rock sediments] because they are so characteristic for a single period of time," Schmidt said.
Terrestrial regions changed as much as marine environments did during these shifts, he added, but not all of these changes registered at a microscopic scale.