Is the Shark a Living Fossil?
There are over 350 species of shark. These remarkable creatures range from about the size of a shrimp to the whale shark that can be over 60 feet long. Most people view sharks as an ancient form of primitive fish, often because they are popularly presented to the public as a so-called "living fossil."
The truth is, sharks are not primitive or simple. In fact, scientists who classify living things are uncomfortable classifying sharks as fish, preferring instead to call them "fish-like vertebrates." Unlike all other fish, the shark has no skeleton. In fact, the shark's skin serves as the anchor for its muscles just as bones serve for anchors in other animals. Unlike fish, sharks have no gill coverings and even have a placenta very much like mammals!
Sharks are also much more complex than fish. They have sophisticated sense organs, their brains are much larger compared to body weight than fish, and they can learn a route through a maze as well as laboratory rabbits. Sharks are also socially complex, and they communicate with each other in a variety of ways.
Among the many kinds of creatures God has created using His unlimited imagination, it appears that He followed some similar themes in each kind. This offers us a better principle than does evolution for classifying living things, which arranges them from simple to complex.