360 to 380 million years ago, during the late Devonian period, there lived a huge species
of predatory fish that grew up to 20 feet long and weighed up to a ton.
That fish was Dunkleosteus, and it lived far before the dinosaurs did.
The Devonian was a period on planet earth where fish reigned king, and the king of all
kings was Dunkleosteus.
But for the next few minutes, lets imagine a hypothetical timeline where old dunks didn’t
go extinct when it did.
What would the cause and effect have been?
That’s what we’re going to talk about on today’s episode of life’s biggest questions.
Hello and welcome back to life’s biggest questions, the channel that imagines the impossible.
I’m charlotte dobre.
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Even though it was basically a giant fish, Dunkleosteus was one of the most terrifying
predators ever to exist.
It kind of looked like a submarine, but in the shape of a fish.
It was armored and had extremely thick, muscly skin that was difficult for its enemies to
puncture.
It also had a distinct shaped mouth, a beak, somewhat like that of a parrot.
It didn’t have teeth, but it had an extremely powerful bite and two bony plates, and with
them could bite down at a force of 6 thousand pounds, right up there with the megalodon’s
bite force.
Its jaws were so powerful that they killed instantly, and could easily slice through
a large victim and break them clean in half.
experts think that dunkleosteus’ mouth was so big, it may have just swallowed its prey
whole.
That being said, it was believed to have been a relatively slow swimmer.
Dunkleosteus Fossils have been discovered all over the world, in north America, in africa,
and in Europe.
Interestingly, it lived at the same time as the Coelacanath (KOALAKANTH), a species of
fish that didn’t go extinct and still exists today.
Granted, they are rare, but they can be found off the east coast of Africa near the Comoro
islands, as well as off the coast of Indonesia and in the Indian ocean.
So why did dunkleoseus go extinct and not koalakanth?
Well right around the time of its extinction, oxygen levels in the ocean dropped significantly.
A drop in oxygen means the big fish that needed it wouldn’t be able to survive, and neither
would much of the marine life.
This mass extinction killed off between 79 percent and 87 percent of all marine species,
including dunkleosteous.
for many millions of years after that, smaller fish flourished until marine dinosaurs.
At the same time, at the end of the devonian period, that was when the race to the land
began.
Vertibrates began to leave the water.
Like the ancestor of all four limbed vertibrates, tetrapods.
Their fins eventually turned into legs.
In the hypothetical world where dunkleosteous didn’t go extinct, the thing that was responsible
for killing it off would not have happened.
Oxygen levels in the world’s oceans would have had to remain at high levels for dunkleosteous
to not go extinct and that would have set off a domino effect.
One of the main reasons why a drop in oxygen occurred is because land plants began to flourish.
These land plants created nutrients that got swept up into the oceans, and was then consumed
by algae which multiplied.
But then when the algea died, bacteria took over, and that’s what consumed all the remaining
oxygen and caused the end of the Devonian period.
Without this drop in oxygen, dunkleosteus and other species of giant fish would have
continued to thrive, and the rest of marine life would too.
The devonian period saw an impressive array of different species of fish unlike anything
that exists today.
Our oceans would have been extremely lush with vegetation to create the oxygen.
Perhaps if there were no drop in oxygen, the devonian period would have continued on for
even longer, or perhaps, not have ended at all.
There might not have been a race to the land, and eventually that might have meant humans
would not exist.
Sure, there may have been a race to the land at some point, but that wouldn’t have occurred
until much later.
If the race to land didn’t happen when it did, Who knows how evolution would have been
affected by this, but one thing is for certain, the world’s inhabitants would look a lot
different than they do.
Perhaps even aquatic looking in nature.
The earth’s oceans would become more and more diverse with every passing millennia.
Perhaps even humanoid sea dwelling beings would have evolved from some types of fish.
You know that dude from The shape of water?
Yeah, kind of like that.
But these humanoids would still have to worry about dunkleosteus, and other large predatory
fish that would not have gone extinct.
But as I previously stated.
Dunkleosteous was not a very fast swimmer, so maybe these humanoids would just have to
pick up the pace a little bit.
Of course, we don’t have an exact reason why all of these changes in evolution occurred.
It was likely a number of contributing factors.
But as soon as you change one thing about the course of history, especially as vital
as oxygen levels in the ocean, a strange timeline begins to take shape, one where humans might
not exist entirely.
For now, I’m charlotte dobre and you’ve been watching life’s biggest questions.
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