Question

How do fossils provide evidence of common ancestor?

Answer 1

Hint: Fossils are the preserved remains of a living organism which is dead presently but thrived during a past geological age. The study of fossils is known as paleontology.

Complete answer:
The size of fossils vary from one micrometer of bacteria to several meters of different animals and trees. A fossil is known to preserve only a part of the dead organism and not entirely, parts such as bones, teeth of vertebrates or exoskeletons of invertebrates are mostly the ones mineralized. The process of fossilization are of different types such as- permineralization, casts and molds, authigenic mineralization, replacement and recrystallization, adpression and bioimmuration.

The age of the fossil can be determined using radiometric dating techniques which also help us to get an idea about the geological period during which this organism lived. Fossils help to identify the similarities as well as differences between organisms that exist currently and extinct organisms. Similarity in structures and anatomies found between them can be a proof of them having a common ancestor. This way of determining common ancestors is most suitable for organisms that contain hard body parts such as bones, teeth or shells as these structures are fossilized and not the entire organism. But because all the fossils have not been discovered and all organisms do not form fossils on death this way of determining common ancestors is not very effective.

Note: Fossils other than giving us information about the extinct organisms and their common ancestors can also serve as medicine. Fossils have been found to be effective against stomach acidity and mineral depletion.