Gene distribution changes over time, across successive generations, to give to the different generations of the offspring. As time goes on they change.
In this video, it shows the ancient types of whales overtime. They evolved from living on the land and then lived in the ocean. They used to have legs until they moved into the water and evolved from legs to fins.
The theory of evolution explains how the enormous variety of life could come into existence. This video will let people understand the science behind evolution and how the process continues. Evolution will always occur and continue in life.