Comparative Anatomy

What I learned is that webbed feet on a frog improved its swimming abilities but One thing I wonder is how long did it take for the frog to get webbed feet. Actually breaking down an organism to find features and abilities they have is amazing how long the way they've came. 

 

Document: https://docs.google.com/document/d/1ElUrYrJSm3TaQyGuh_uDeqrzHTbyuDJzZpb9OtXOR9A/edit?usp=sharing