NCERT Question 8 - Chapter 9 Class 10 - Heredity and Evolution

Explain the importance of fossils in deciding evolutionary relationships.

Answer:

• Fossils are preserved remains of organisms that existed on Earth at some point in the past. 
• When an organism dies , most of it decomposes and gets broken down into simpler forms .
• But some parts do not decompose quickly, traces of such parts (fossils) help us to find evolutionary relations .
• Thus, by studying the characteristics and age of the fossils , we can study evolutionary relationships .

For Example -  

• Fossil records have been used to study the evolutionary relationship between birds and reptiles .
• Some dinosaurs had feathers to provide insulation from cold weather , not for flight.
• But after years of evolution, birds now have the ability to fly with the help of wings.
• Archaeopteryx is the fossil form of an organism that was found as an evolutionary link between reptiles and birds.