Scientists have found a "microworld" of 220-million-year-old life trapped inside tiny drops of ancient amber. The fossilized plant resin preserved bacteria, fungi, algae, and protozoans (one-cell animals) from some 220 million years ago, in the Triassic, the era when dinosaurs emerged.

Surprisingly, these microscopic organisms look very similar to those of today. Researchers at Humboldt University of Berlin, Germany, reported that the microbes have undergone few or no physical changes since the Triassic (245 million to 208 million years ago).

During many of the Earth's geological epochs and climatic shifts, countless species have appeared only to vanish or evolve, but microbes appear to have changed very little related to present-day microbial species.

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," said Alexander Schmidt from the research.

"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."

"Although there were big changes in the composition of forests from the Triassic to recent [times] … their microhabitats probably changed little, even during extinction events," Schmidt explained.

Many fossil species have been found in amber, like the oldest known bee and so on, but samples older than about 135 million years are very rare. The amber comes from near Cortina d'Ampezzo, a village in the Dolomites mountain range in northern Italy. During the Triassic, this region was wrapped by humid forests on the coast of an ancient sea.