Because of the conditions necessary for their preservation, not all types of organisms that existed in the past have left fossils that can be retrieved.
Approximately only 1/10 of 1% (0.01) of living things ever become fossilized!
- In order for a fossil to form, the organism's remains must not be significantly disturbed by a scavenger/decomposer or destroyed by erosion and other natural forces. Therefore, organisms or parts of organisms that make up fossils are most likely buried quickly and deeply.
- examples: woolly mammoth found in ice, insects found in amber, animals found in peat bogs, mass burials from flash floods or volcanic ash falls.
- Soft body parts, such as skin, muscle, fat, and internal organs, deteriorate rapidly and leave no trace. Casts of such tissues are rarely found. Similarly, organisms that are soft-bodied creatures, like jellyfish, are very uncommon fossils while hard body parts (such as teeth and shells) fossilize easier.
- Molds can be made of organisms. However, the organism must be buried in sediment after which its tissues dissolve and are replaced by dissolved minerals which make it a solid. Without the correct minerals this process cannot take place.
- The fact that extremely few living things are preserved long enough after death to become fossils makes the large collections of fossils in the museums of the world quite remarkable!
- Fossilization (fossilized) - to convert into a fossil; replace organic with mineral substances in the remains of an organism.
Some Common Way's Ancient Organisms
Could be Buried Quickly and Deeply and become Fossilized
How some fossils are formed
How are trace fossils like dinosaur footprints preserved?
- What is taphonomy?
- With moldes, sometimes the rock as the appearance of the organism. Sometimes, all traces of the organism are lost but an external mold is formed around the body and is preserved. Sometimes internal mold forms when material is precipitated inside an organism (ex: a marine shell or the hollow stem of a plant). What are some real-world examples of this. What did scientists conclude or learn from these fossils?