IF FOSSILS look like bacteria, are they bacteria? That’s the question that divided researchers over tiny structures in the famous Martian meteorite ALH84001, and it’s now at the heart of fierce debate over imprints in ancient terrestrial rock. The fossil furore could rewrite the textbooks on the early evolution of life on Earth.
At issue are microscopic patterns of filaments embedded in 3.5-billion-year-old rock from Western Australia. William Schopf of UCLA, who first described them over a decade ago, says they represent 11 different bacterial species, including photosynthetic cyanobacteria. This would make them the oldest fossils ever found.
Schopf has…
