Preservation of Organisms in Amber
Amber formation is a very different way that fossils form. Amber is also called fossil resin. The resin is excreted from pine trees and buried under sediments, and over time, polymerization takes place and hardens the resin. Amber is in itself a plant fossil, but even more interesting is when organisms are trapped inside the amber. Fossilized organisms found in amber include insects, spiders, plants, fungi, bacteria and even small geckos.
Here is the step by step process of how amber fossils form:
- Resin is produced by coniferous trees as a defense mechanism or to heal holes. Essential oils compose most of the resin.
- Resin flows down the tree and traps animals, bacteria or plant material.
- Polymerization changes the structure of the resin and hardens it. This stage is called copal.
- The concentration of essential oil decreases and the polymerization continues.
- After million of years, it hardens into amber.
Amber is up to 300 million years old, the Carboniferous Period, though most are from the Jurassic Period or younger, 140 million years ago.
Amber is so interesting because it preserves whole organisms including the soft tissues, and sometimes it can preserve a whole ecosystem by entrapping animals, plants and bacteria at the same time. It is possible to extract and sequence DNA from preserved species, but there will rarely be enough to replicate the organism.
The majority of amber is found in the Baltic Sea Region from pine trees in Russia. They wash ashore on beaches in Germany, Poland, Lithuania, Denmark, the former Soviet Union, Great Britain, Estonia, Latvia, and Holland. Amber is also found in Colombia.