Fossile

Fossil, in the broad sense, refers to the preserved remains or traces of organisms from geological time. The term derives from Latin fossilis, meaning “dug up.” In some languages the equivalent word is fossile. Fossils provide evidence about past life and the environments in which it existed.

Fossil formation occurs through several preservation pathways. Body fossils result from processes such as permineralization, where mineral-rich fluids fill and replace tissues; replacement and casts; and carbonization, which yields a thin film of carbon. Other forms of preservation include molds and impressions, preserved shells or bones in sediment, and entombment in amber, tar, or ice. Rapid burial and anoxic conditions enhance the likelihood of exceptional preservation.

Two major fossil types are recognized: body fossils (actual remains of organisms) and trace fossils (evidence of activity, such as footprints, burrows, or coprolites). Lagerstätten are sites with unusually detailed or diverse preservation, offering rare glimpses of ancient life.

The fossil record enables reconstruction of evolutionary history, ancient ecosystems, and past climates. Dating relies on relative methods (stratigraphy and faunal succession) and absolute methods (radiometric dating). Radiocarbon dating is effective up to about 50,000 years; older data come from methods such as uranium–lead or potassium–argon dating.

Limitations and biases affect what is preserved and discovered. Soft-bodied organisms, certain environments, and uneven sampling reduce representation in the fossil record. Despite these constraints, fossils remain central to paleontology, informing our understanding of life's history and the dynamics of past Earth systems.