The preserved remains of animals or plants or other organisms from the distant past are called fossils. These fossils tell us about many extinct animals and also give insights into how the evolution could have taken place.
Evolution is the successive alteration in inherited characteristics over an extensive span of time, typically over generations.
- Evolution relies on genetic variation in a population which affects the physical characteristics of an organism. Certain physical characteristics may give advantage to the individuals which can be transferred to their offspring.
- The evidence of evolution is one of the fundamental keystones of modern biological theory. It is the only way which can prove all the proposed theories of evolution.
- We have a number of evidences to prove the biological evolution namely fossils, comparative anatomy and embryo development pattern.
Fossils and age
They are the remains of the non-degraded parts of living beings found within rocks. The layer from which the fossil is recovered decides the age of the fossil. The fossils found deeper down are older compared to the ones found in the upper layers. They give an idea of the condition of the earth in that specific era. The study of fossils is called palaeontology. Thus, fossils are called paleontological evidences.
Estimation of fossil
We could estimate the age of fossils in two ways.
- The first procedure: In this method, we assume that the fossils which we find at the topmost layers are more recent ones while at a deeper layer, the fossils found are older.
- The second method: ,An estimation of the ratios of different isotopes of the same element in the fossil is carried out.