Ammonite, a prehistoric relative of the squid, lived in a twisted spiral shell and swam in the sea. When he died, the soft tissue of his body has rotted or were eaten by other animals (1). Hard shell on the sea floor gradually covered by sandy sediments (2). And sink, and the sand has turned into rock that rose to the surface as a result of tectonic movements (3). Erosion of the breed has led to the emergence of fossilized shells on the surface (4).
Fossils – fossils that once lived organisms, preserved in rocks. Most organisms were either eaten or died a natural death, and their soft tissues are completely rotted. However, the solid fabric – shells, bones, teeth, horns and claws of animals or the bark, cones and seeds of plants sometimes persist. Sometimes from ancient organisms remain the only fossil footprints – paw prints, egg shells or droppings.
Some sedimentary rocks have several layers containing fossils, as shown in this illustration, the shell. It was formed after he killed thousands of Ammonites and their shells accumulated on the sea bottom.
Hard tissues like bones and teeth are buried under sedimentary formations, for example, under the sand on the coast, river or sea silt. Pananagutan dissolve in surrounding water, is replaced by minerals contained in the water, and over time, the fine particles turn to stone. The remains that have preserved their original shape, now are fossils.
Viscous resin, exuding from trees and other plants that can harden and turn into solid amber yellow. Sometimes in amber, you can find insects and other small creatures that are stuck in the tar and preserved to the smallest detail.
For the formation of fossils requires many thousands or even millions of years, and they are found only in sedimentary rocks. Scientists-paleontologists dig, study the form and structure of fossils found and compared with similar tissues of organisms living in our time. Thus, were able to detect many types of dinosaurs, mammoths and other animals that inhabited the Earth millions of years ago.