Explain:
1. Fossilization
Answers
Answer:
FOSSILIZATION
As we know that formation of fossils is called fossilization. Fossilization ocas in bogs, lava and at the bottom of the deep waters where there is little Oxygen and rate of decay is slow or absent. Most of the fossils are found in sedimentary rocks which develop at the bottom of a deep lake and sea. Dead bodies of terrestrial plants and animals are brought near by streams, rivers and rain wash. Alongwith dead bodies of aquatic organisms, they settle down at the bottom. Sand and silt settle over the dead bodies. Normally, the dead bodies decompose completely. However, sometimes conditions exist when decomposition is low or absent, for example hot mud, acidic environment and hevy deposition of silt. Under acidic conditions some silica may penetrate the cells of dead organism and form perfect fossil. In Aadhar cases slow decay continues. It leaves only hard parts. Impressions, moulds and casts may be produced if there are no hard parts. The sedimented mud and sand harden to form rock. With the upheavals in the interior of earth, the rock containing fossils may come to the surface and expose the fossils.
DETERMINATION OF THE AGE OF FOSSIL:
Age of the fossil will be the same as that of the rock in which it is found. It is found out by two methods, relative dating and absolute dating.
1. RELATIVE DATING:
Fossils closer to the surface are more recent than the fossils present mid way and once present mid way more recent and the fossils present in deeper layer. Relative position of the rock and the rate of its erosion can also indicate the same.
2. ABSOLUTE DATING:
Fossil or piece of fossil containing rock is analysed for content of uranium and lead, radioactive potassium and argon or contents of radioactive carbon called Carbon - 14. Carbon dating is meant for calculating the age of a recent fossil. Uranium-lead dating and potassium-argon dating are used where the age of fossil is several millions of years. Electron spine resonance is the latest technique to determine the age of the fossil directly without breaking any part.
For example: dead body of dinosaur buried in mud which also got compressed into rock, above the rock containing invertebrate fossil.
Answer:
Fossilization is the process by which a plant or animal becomes a fossil. This process is extremely rare and only a small fraction of the plants and animals that have lived in the past 600 million years are preserved as fossils.
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