Final answer:
Bony fish have fins that fall into two categories: ray-finned and lobe-finned. Ray-finned fish have fins supported by flexible spines, while lobe-finned fish have fleshy, muscular fins similar to the limbs of terrestrial vertebrates.
Step-by-step explanation:
The type of fins that bony fish have can be classified into two main groups; ray-finned fish and lobe-finned fish. Ray-finned fish, which comprise the majority of bony fish species, have fins that include thin, flexible spines known as 'rays' covered with webs of skin. These fins do not contain muscles but are controlled by muscles located in the body wall.
In contrast, lobe-finned fish possess appendage-like fins with a fleshy, muscular structure supported by bone. Living examples of lobe-finned fish are the lungfish and coelacanth, and it is this group that is considered ancestral to amphibians. The distinct fin structures relate to their differing modes of life, with ray fins being more adapted to maneuvering in a variety of water environments, while lobe fins have features that are considered a precursor to the limbs of terrestrial vertebrates.