What is the most common fossil found

What are fossils?

Surely you've found fossils before - maybe without knowing it. Traces and remains of dead and extinct creatures that are enclosed in stone are called that. This is also of interest to Lucie, 9 years old: What are fossils and which are there often? she asks us.

Ammonites are among the most common fossils found. Source © Ann Baldwin, Shutterstock

The word fossils is derived from the Latin word “fodere” (dig) and means “dug up”. Scientists who study these fossils are called paleontologists. They examine fossils to learn more about the evolution of the earth and its history.

Fossils exist in all shapes and sizes: from the huge 22-meter-long brachiosaur skeleton in the Berlin Natural History Museum to tiny, millimeter-sized conodonts - fish-like vertebrates that belong to the microfossils. In fossilized form there are, for example, plant prints such as leaves, footprints of dinosaurs, bones of mammoths, dragonflies, snails or even excrement, i.e. the excrement, of extinct animals.

How are fossils formed?

Not every living being that has died is preserved for posterity. Normally, predators, scavengers and microorganisms such as bacteria, maggots and worms ensure that animal and plant remains are eaten or broken down. The most important requirement for fossils to be formed is the lack of oxygen. And that always happens when animals or plants are firmly enclosed: for example, insects that drown in tree sap or leaves that sink into the bog.

Most often, fossils are found in rocks that were formed in the sea, but also in lakes and rivers. When the organisms living in the sea die, they sink into the depths and begin to rot. Usually only the hard parts such as shells, bones and teeth remain, which are embedded in loose sand and mud. The faster it is embedded, the better a fossil will be preserved.

If the emplacement layer is covered by further layers, it is converted into solid rock. The fossil remains petrify as minerals and bones are deposited in the shells and bones. If the rocks are lifted out by forces of the earth's interior and exposed again by erosion, the fossils become visible.

What are ammonites?

Particularly common fossils are ammonites. With a bit of luck, you can even spot them on stones that can be on the edge of each field. Ammonites populated all seas for 350 million years and are known as marine cephalopods. They also lived during the time of the dinosaurs, and they died out around the same time as them, about 65 million years ago, towards the end of the Mesozoic. They include 12,000 species, which are divided into about 1,500 genera.


 

You can find out more on the subject in WAS IST WAS Volume 69 Fossils. Traces of life