Q3 Page 156 - Chapter 9 Class 10 - Heredity and Evolution

What are fossils? What do they tell us about the process of evolution?

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 .

• Examination of each layer of the Earth for fossils gives us information about the changes in the Earth’s surface over the years. 
• We also get information about the organisms that belonged to that region.
• Fossil records have been used to study the evolutionary relationship between birds and reptiles .
• It also shows how mammals evolved over time .
• Fossil remains show that pteridophytes and gymnosperms are ancestors of angiosperms .
• Stages of Human evolution could also be traced using fossil remains.