Impacts on humans
Sharks have always been seen as a dangerous animal that we should be afraid of but for the most part, they usually aren’t very aggressive toward humans. From the 400 known species of shark, only 30 of those species have been in unprovoked attacks and only 15 of those 30 species were considered dangerous. But we have seen reports of shark attacks were people in the water were attacked and the survivors were able to see that it was a shark attacking them and even in some cases they were even able to tell what type of species of shark it was. It was seen that from 1967 to 2007 there were around 1,600 unprovoked attacks, which is around 40 attacks a year. So with this information, we can see that there isn’t an overwhelming amount of shark attacks but it does end up affecting us when we are in the ocean.
Other ways shark impact us is how we use shark body’s and what we use them for. One example of this is that some lotions actually use shark to create their product. Then we also use their meat to create certain foods and some of those foods are Fish and chips, Mako steaks, and White Fish Fillets. The skin of a shark is also used for a good amount of thing most of us use in our everyday life and some of these products are wallets, shoes, and furniture. So without even knowing sharks are used in some of the most basic supplies we use on a daily basis.
Ecological impacts
Sharks play an important role in keeping the ecosystem of the ocean healthy. The way sharks keep our oceans ecosystem healthy by removing the weak and sick from the ecosystem and this is possible for them because they are the apex predator of the ocean. So since they are predators they have some control over their preys spatial habitat and this, in turn, affects their preys feeding pattern and the diets of other species. One example showing this was a study from North Carolina that shows the loss of great white sharks has been affecting the population of rays by allowing them to increase in numbers rapidly. The result of this rapid increase of ray they are starting to eat more scallops that can be produced which is causing them to move to other bivalves.
This shows how important sharks are for our ocean ecosystem because if they aren’t there a certain species has the potential to monopolize a limited resource and I believe that the first warning of this becoming a possibility is the rising population of rays. Furthermore, if the shark ends up becoming extinct the biodiversity and the density of individuals would decrease substantially.
Evolution and phylogenic tree with our organism
Around 450 million years ago was the Silurian period and this was when the shark first started to develop as its own species. At this point in time, the ocean was filled with much bony fish and one of them was the Acanthodian and this was the first ancestor of the modern shark. The Acanthodian is also known as the spiny sharks and it was the first fish to get the physical characteristic and the skeletal structure that defines a shark.
Then about 50 million years later is when the first fully developed shark appeared. We don’t know a lot about this shark but from the fossils, we do have we could estimate that it was about 16 inches long and it had an eel-like body and it also lived in freshwater. Then during the late Devonian era, the first modern incarnation of the shark appeared. This shark looked more like the present-day shark compared to its ancestors. It was 6 feet long and it had a streamed line body with 5-7 gills and a dorsal fin.
360 million years ago was the time that the sharks started to dominate the oceans. This was also the time when sharks started to become more diverse and where more subspecies of shark started to appear as well. It was so diverse that it had 45 different families of shark.
The Jurassic era started around 200 million years ago and the sharks that came from this era were the predecessors of the sharks we know today. In this era, sharks started to develop flexible and protruding jaws so they could hunt larger prey and they also developed tail fins that would allow them to swim faster and more efficiently.
The Cretaceous era was around 145 to 65 million years ago and most of the sharks seen today developed during this era. sharks that developed during this era include the goblin shark, whale shark, and basking shark. This was also the time period of the Lamnidae shark which is the predecessor of the modern sharks like the great white and the tiger shark.
Then in the early Cenozoic era which was about 60 million years ago, and this was the era where the most famous shark appeared which is the megalodon. The megalodon was the biggest ocean predator to ever exist. It was 65 feet long and weighed over 30 tons and to top it off it had 7-inch-long teeth that helped it eat whales.
