What does fossil evidence indicate about the order in which these three vertebrates evolved a bony fish with jaw jawless and leglike fins?

1. Jawless fish

2. Bony fish with jaws

3. Leg-like fins

Jawless fish, such as lampreys and hagfish, were the first vertebrates to evolve. They appeared in the fossil record over 500 million years ago. These fish had no jaws and used their mouths to suck food in.

Bony fish with jaws, such as sharks and tuna, evolved from jawless fish around 420 million years ago. The evolution of jaws allowed bony fish to feed on a wider variety of food and become more successful.

Leg-like fins, such as those found on the arms and legs of amphibians and reptiles, evolved from bony fish with jaws around 360 million years ago. The evolution of leg-like fins allowed vertebrates to move onto land and explore new habitats.

This order of evolution is reflected in the fossil record. Jawless fish fossils are the oldest, followed by bony fish with jaws, and then leg-like fins.