Based on the studies conducted by experts, sharks have been on Earth for more than 450 million years.
Over that span of time they have evolved in a variety of ways in order to make the environment that they have
access to one that can work for them. The way in which we know them today is believed to be the results of
evolution that took place about 100 million years ago.
Of course not all of the sharks that once were on Earth are available today. There are records from early
fossils to indicate that at least half of them have become extinct. We have just over 1,000 species of sharks
remaining today. However, just as many if not more of them have already been eliminated and we will never get to
see them on Earth again.
Sharks Evolutive Adaptations
Many of the early forms of sharks were quite small. There is evidence to suggest they looked more like fish. Many
of them were similar to eels as well. Their faces featured noses that were round rather than pointed. They also
didn’t have a brain as large as it is today. That is a very important point to make though. More than 2/3 of the
size of a brain today for a shark is for the senses. Mainly their ability to smell. This is one of the areas where
sharks have significantly been able to evolve and to become a more intelligent species.
Their teeth were also quite different than they are today. Instead of being razor sharp they were smooth. However,
these early ancestors definitely had the rows of teeth that were replaced like they do today. This could indicate
that early sharks fed upon plants in the water instead of being meat eaters as we know them today. This could be an
indication that something occurred that made it impossible for plant life to grow for a while. In order to survive
they started to consume other living creatures in the water.
They likely didn’t swim around as much back them as they do today either. This is evident by the shape and size
of their fins. They may have had to evolve in this physical characteristic in order to move long distances in
search of food.
Characteristics Mantained through Evolution
There are many things about the sharks that haven’t changed though that are worth mentioning. They have the same
design when it comes to the skeleton that is both inside and outside of their body for protection and movement.
They also have several slits for their gills which allow them to be able to breathe.
The fact that sharks are found in water all over the world also says a great deal about their ability to evolve.
The different species were able to adapt to fresh water and to salt water environments. They were also able to live
in a variety of different temperatures. All of this is quite amazing to researchers. Even so, there is still a
great deal about the evolution of sharks that we don’t have the answers to yet.
Are sharks going to be able to successfully continue to evolve? That is a concern for many experts. They fear
that humans have taken over too much of the control so sharks will find it difficult to continue to evolve for
survive. This would explain why many of the species are in danger of becoming extinct. Only time will tell though
if sharks are able to continue being successful when it comes to their survival skills. They have certainly done an
amazing job of it in the past.