The importance of the fossils and the suitable conditions for the fossils formation
The suitable conditions for the fossils formation
The organism body must be buried immediately after death in a medium that preserves it from the decomposition , The organism must have hard skeleton , The suitable medium must be found in which the mineral material replaces the organic material of the living organism .
The importance of the fossils
The fossils help in studying the life evolution which is known by the fossil record , The fossils exist in the rocks of the different areas . And the fossil record indicates the extinction and the evolution of the organisms .
Studying the fossil record showed that the life started first in the sea , then established on the land . The organisms always developed from simple to complicated as :
|The archaeopteryx fossil is considered a link between the reptiles and the birds .|
The fish were the first vertebrates that appeared , followed by the amphibians , then the reptiles , and finally the birds and the mammals appeared together .
The invertebrates ( such as the coral and the mollusks with the shells ) appeared before the vertebrates .
The algae appeared before the mosses and the ferns . The angiosperms appeared before the gymnosperms .
The fossils help in the age determination of the sedimentary rocks , And you know that the index fossils indicate the age of the sedimentary rocks , Because the age of the rocks is the same age of the fossils existed in them .
|The fossils help in the age determination of the sedimentary rocks .|
The index fossils are the fossils of the organisms that had lived for a short period of time in the past , and had a wide geographic distribution , then became extinct .
The fossils help in the petroleum exploration . You know that the geologists take the samples from the rocks of the exploratory wells , when they search for the petroleum .
|The fossils help in the petroleum exploration .|
These samples are studied under the microscope , And if they contain microfossils like the foraminifera and the radiolaria , They will point to the age of the rocks existed in the exploratory wells , and the suitable conditions for the petroleum formation .
The fossils help in figuring out the paleoenvironment . The fossils give an idea about the environment in which they lived during the old geologic ages , and also they indicate the climate of these ages .
The coral fossils indicate that the environment where they live was clear warm shallow seas .
The ferns fossils indicate that the environment where they lived was a hot and rainy tropical environment .
The nummulites fossils are found in the limestone rocks of Gebel El-Mokattam , and indicate that this area was a sea floor more than 35 million years ago .