Question

What are fossils? How do fossils provide the guide for evolution?

Answer 1

Hint: Fossils are the remaining traces of organisms that existed before our period and they get preserved by natural processes. By analyzing fossils we can interpret how life forms existed millions of years ago.

Complete answer:
Fossils are acquired by digging into the land where preserved remains, imprints, or traces such as skeleton, shells, remains trapped in amber or ice, petrified logs, exoskeletons, hair, and genetic components of pre-existing organisms. The study of fossils is known as paleontology and a person who practices it is called the paleontologist. Analysis of fossils and estimation of its age, the process of formation, and relationship with existing life forms are an important aspect of paleontology.
Fossils the age of a fossil is analysed using carbon dating, and the preserved DNA is compared with the existing life forms to understand the family tree and connection with the ancestral lifeforms, this is how fossils become the guide for evolution. In nature, fossils are formed by different processes such as permineralization, authigenic mineralization, replacement and recrystallization, depression, carbonization, and biosimulation.
The size of fossils can vary depending on the size of the organism, where it can be the remains of bacteria to a dinosaur. Fossils are important in understanding the formation of the existing life forms including the homology of species. It also provides the genetic similarity of organisms, knowledge about the geographical patterns, and variation in life forms.

Note:
 -The fossils we currently obtain are only the hard body parts of organisms. The soft-bodied organisms do not remain to become a fossil as they will be decomposed by microorganisms.
-A major limitation of fossils is that only a small percentage of total fossil content has been discovered. Most of the fossils will not be complete as a major part of them would have gone by degradation or by weathering.
-The oldest fossil found to date is 3.5 billion-year-old microscopic fossils. This was found by the University of Wisconsin-Madison from Australia.