The Science of Fossils
Did you know?
- Fossils aren't always bones, and they don't always come from dinosaurs. Plants, cells, seeds, footprints, feces, eggs, and marks from ancient water or soil are just some examples of the other things that can be fossilized.
- Usually, only the hard parts of organisms— such as bones or shells—become fossils. Organs, muscles, soft tissue and skin normally decay rapidly and never make it to the fossil stage.
- While most fossils are tens of thousands or millions of years old, the minimum age for a fossil is 10,000 years old.
- Fossils of sea creatures, such as snails, corals and clams, are much more common than dinosaur fossils.
- Coal is actually the fossilized remains of whole forests that have decayed and condensed underground over time.
- People who study fossils are called Paleontologists.
The fossil formation process, step by step:
- An animal or organism dies, preferably in a watery environment.
- The remains become buried in mud and silt.
- Soft tissue decomposes, leaving behind bones, shells, teeth, claws, and other hard matter.
- Time passes, and layers of sediment build up over the remains— eventually hardening into rock.
- The original bones and other materials begin to decay, allowing minerals to seep in to replace them cell by cell. This process is called "petrification."
Not all fossils are created equal, and not all fossils are formed in the same process of petrification. Here are some examples of unusual fossil formation:
- Flies, mosquitos, and other insects that get stuck in tree sap can become fossilized when the sap hardens, turning into the semiprecious material called amber.
- Volcanic eruptions can form fossils when organisms become trapped and encased in lava and ash.