Why Did Sharks Survive the Mass Extinction That Wiped out the Dinosaurs?
There were five mass extinctions according to the researchers. Every time, a major part of the species population was annihilated from the earth. The fast and drastic change in the climate and ecosystems led to the downfall of major animals ruling the earth at that time. The last mass extinction killed all the big dinosaur species 65 million years ago. How did sharks survive the dinosaur extinction?
Sharks evolved and existed on the earth before the dinosaurs and continue to this date. You will be surprised to know that sharks date back to 450 million years ago according to the oldest fossil found. They are at least 90 million years older than even trees. Then, how did they survive the latest mass extinction and outsmarted dinosaurs? Read through the blog to know more about it.
How Did Dinosaurs Get Extinct?
As per the geological evidence collected from the fossils and earth samples, it has been found that the last mass extinction happened 66 million years ago between the Cretaceous Era and the Palaeogene Era.
This mass extinction occurred when a huge asteroid fell on the earth and caused a drastic change in the entire planet’s climate. The impact triggered huge volcanic eruptions across the planet resulting in covering the atmosphere with toxic gases and volcanic ash. Researchers have found that almost all the nonavian dinosaur species ceased to exist in a matter of a few years.
According to the latest calculations from the abundant fossils collected, they ruled the earth for more than 230 million years. This is the answer to the question of how many years dinosaurs survived on earth. The time period when most dinosaur species evolved and lived is called the Mesozoic Era (245 to 66 million years ago).
There were humongous species roaming around the earth and being a part of the ecosystem. The asteroid impact resulted in a huge disaster where all the major species were killed leaving small reptiles, amphibians, fish, and primitive mammals.
The marine ecosystem was not also spared from this series of mass extinction events. It was affected hugely when the bigger predators were unable to survive. This is why dinosaurs became extinct in the marine world and the sharks thrived.
Why Did the Sharks Thrive?
According to the latest research, the scientists concluded that the impact of this asteroid caused a huge crater of 150 km radius. Imagine what tremors the world faced during the impact. Earthquakes, tsunamis, volcanic eruptions and sudden fall in temperature due to the masking of sunlight eradicated a major part of the dinosaur population.
They also revealed that this series of events did not affect the shark species that much. Yes, they were threatened to a considerable extent but nature chose them to survive. This is called the survival of the fittest. The interpretations of the research work done by various scientists are contradictory though.
Some think that the abiotic and biotic drivers of the marine ecosystem led to a favourable space for the sharks to survive this catastrophe. They also hypothesise that the evolution of sharks is also related to these factors.
While we cannot deny the fact of the evolution of sharks, we cannot really conclude that fact that the reasons depicting the answer to ‘how did dinosaurs die?’ did not affect the shark species that much. It is indeed that the food source has reduced considerably but the abilities of the sharks to survive extinction is simply beyond comprehension.
Many researchers suggest that the species at that time might have the capability of regeneration and repair of DNA that led to the foundation of sharks’ survival. We need to consider the fact that the studies on prehistoric shark species entirely depend on the teeth they shed, not the bones or fossils found. It means the existence of shark fossils is much less than that of dinosaurs.
As mentioned earlier, sharks evolved almost 100 million years before the dinosaurs. They were the major predators of the marine ecosystem. In fact, they play an important role in the present ecosystem too. What would have happened if the sharks ceased to exist?
Sharks Survived the Mass Extinction that Killed Dinosaurs
Also Read: Do Sharks Have Vocal Cords?
Why We Can’t Live in a World Without Sharks
Sharks are the major species of predators that rule the sea. They are thus at the top of the food chain in the marine biome. What would have happened if they were wiped out in the latest mass extinction?
They are cartilaginous fish with amphibious qualities of survival. They are very important to maintain the balance of the marine ecosystem. Being at the top of the food chain, they predate and maintain the population of the species below them.
Due to their predation, the food chain is stabilised in the marine biomes. They also help in regulating the population of other species. Simply put, oceanic predators are one of the prime reasons behind the diversity of species in the marine ecosystem.
Threats to the Sharks’ Survival
Even though the sharks have managed to survive the mass extinction, they are facing a huge problem in this contemporary era. We, humans, are killing them at a significantly larger rate for our profit. Apparently, we are a bigger threat than the asteroid wiping out the dinosaurs.
Shark fins are a delicacy across the world. Every year, 100 million of them on average are killed for this purpose resulting in an alarming imbalance in the oceans. Their population is depleting very fast due to such human activities.
There are nearly 350 species of sharks existing on the earth. They vary in diet, size, habitat, etc. All of them are important as they are apex predators. Despite being a sentient species, nearly 6.4 to 7.9% of sharks are killed in every species. They are not bloodthirsty as shown in the movies. Without them, the marine ecosystem may crumble resulting in a bigger catastrophe.
