Fossils are formed when a living organism dies and its remains are quickly buried by sediment, usually in a marine environment or another place where sediment accumulates rapidly. The soft parts of the organism typically decay, leaving hard parts like bones, teeth, or shells. Over time, sediment builds up and hardens into rock, while minerals from groundwater infiltrate the remains, turning them into stone. This process, called fossilization, can occur in several ways, including permineralization (minerals filling cells), formation of molds and casts (where the remains dissolve and leave a cavity filled by minerals), and preservation in amber or ice. After millions of years, geological processes may expose these fossils on the Earth's surface for discovery. Key steps in fossil formation:
- Organism dies and is buried quickly by sediment.
- Sediment accumulates and hardens, protecting remains.
- Organic material decays, leaving hard parts.
- Minerals permeate and replace organic structures.
- Fossils may be exposed by erosion and geological activity.
These processes preserve the shape or even some internal structures of the organism, providing valuable information about ancient life.
