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.
Fossilization is NOT Easy!
Not many plants and animals are lucky enough to last 10,000 years or more and be turned into fossils. When an animal or plant dies its remains usually rot away. Approximately only 1/10 of 1% (0.001) 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, rotted away by decomposers like bacteria, or destroyed by natural forces such as weathering which are all very common. Other factors include whether or not the organism is made up of most hard or soft body tissues, or if the environment is depositing sediment or eroding it, the chemistry of the environment if it would dissolve the materials necessary for fossilization to occur or not, the rate of burial, and many other factors. Some entire taxonomic groups of species that are made up of mostly soft-bodied parts, like jellyfish, are very uncommon fossils because soft body tissues quickly rot away while hard body parts (such as teeth and shells) more easily fossilize.
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!
Factors that can LIMIT the
Fossilization of Living Things:
- How quickly and deeply the organisms were buried.
- The presence of scavengers that consume the remains.
- The presence of decomposers that cause the remains to rot away.
- Natural forces including plate tectonics, and weathering that break down the remains.
- Lack of time for the fossilization process to take place.
- Lack of hard body tissues that make up the organism.
- Environmental factors including not actively depositing sediment, ash or tar.
- The chemistry of the environment not providing the necessary minerals for preservation.
- The likelihood that the preserved remains are even found before being damaged.
Video Guide:
|
|
Topic Tips
- The likelihood of becoming a fossil is extremely rare.
- There are many factors that limit an organism's chances of becoming a fossil.