Write a short note on : Evolution of feathers

Explanation

The feathers of birds also evolved in gradual stages.
The feathers have not evolved firstly in the birds but in the dinosaurs. The dinosaurs are extinct reptiles. In some of the dinosaurs the feathers were not used for flight but provided insulation in cool environment. Later on the feathers changed and became useful for flight. Birds seem to have later adapted to flight by using feathers. The presence of feathers in the birds suggests that the birds and reptiles are closely related groups. The dinosaurs were reptiles and had feathers, which were later used by birds for flight.
Thus, the feathers in the birds are evolved for flight from some of the dinosaurs having feathers.