Fossils are the preserved remains, impressions, or traces of organisms that lived in past geological ages. They can include bones, shells, exoskeletons, imprints, objects preserved in amber, petrified wood, and even biochemical remnants like DNA
. Fossils may also be trace fossils, which are not the remains themselves but evidence of an organism’s activity, such as footprints, burrows, or fossilized feces (coprolites)
. Fossilization typically occurs when an organism dies and is quickly buried by sediments like mud or sand, often in ancient seas, lakes, or rivers. Over time, the soft parts usually decay, but the hard parts such as bones, teeth, or shells can be mineralized or replaced by minerals, turning them into rock- like replicas of the original organism
. This process is called fossilization and includes mechanisms like permineralization, replacement, and carbonization
. Fossils vary greatly in size, from microscopic bacteria to large dinosaurs and trees. They provide crucial information about the history of life on Earth, evolutionary patterns, and ancient environments. The collective body of fossil evidence is known as the fossil record, which scientists study to understand how life has changed over millions of years
. In summary, fossils are the preserved physical evidence or traces of ancient life, formed through natural processes that protect and mineralize biological material over geological time.
