Fossiile

Fossiile, the Italian word for fossils, are preserved remnants or traces of organisms from past geological ages. They provide direct or indirect evidence about ancient life, environments, and ecosystems, and are the primary material studied in paleontology.

There are two broad classes of fossile. Body fossils are preserved parts of organisms, such as shells, bones, teeth, or rarely soft tissues. Trace fossils record evidence of activity, behavior, or life processes, including footprints, burrows, nests, and coprolites (fossilized feces). Together, body and trace fossils illuminate anatomy, physiology, behavior, and the ecological roles of extinct organisms.

Preservation occurs when an organism is rapidly buried and protected from decay, followed by mineralization or other stabilizing processes. Common pathways include permineralization (minerals infilling remains), replacement (original material replaced by minerals), carbonization (soft-tissue compression into carbon), and molds or casts (impressions of the original form). Preservation can also occur in amber, ice, or tar, capturing delicate features or whole organisms.

Dating fossile relies on both relative and absolute methods. Relative dating uses stratigraphic context and index fossils to establish a sequence of events. Absolute dating employs radiometric techniques such as uranium–lead, potassium–argon, or carbon-14 dating to estimate numerical ages. Together these methods situate fossils within the geological timeline and enable reconstruction of evolutionary histories.

Significance and limitations: fossile records document the history of life, major evolutionary transitions, and past environments, contributing to our understanding of climate change, extinction events, and biodiversity. They are uneven due to preservation biases and sampling gaps. Exceptional sites, or Lagerstätten, preserve detailed soft-tissue and ecological relationships; notable examples include Burgess Shale and Chengjiang.