What if Tiktaalik had never walked on land?

In this day and age, one certain creature is denied of much of the fame it deserves. 375 million years ago, the concept of humans were foreign on the fiery ball of land we now call Earth. The majority of our world was still covered by ocean, and within these oceans laid countless species of fish and bacteria, without an idea of life outside of the water. That was, until a certain fish stumbled onto land...

Personally, I think he's adorable! (source) 

If you know me well, you know I could discuss the charm of this guy's beady little eyes for hours. But, aside from being so handsome, this crocodile-resembling fish is the reason humans exist today, and it's known as Tiktaalik. Tiktaalik was unique in having a blend of traits from both fish and land animals, becoming the most likely ancestor for the world’s first land vertebrates.

Tiktaalik first emerged from land during the Devonian period. Second in infamy only to the age of dinosaurs, the Devonian period was about 420 to 360 million years ago, often known as the “age of fishes." During this time, sea levels were high and the climate was much warmer and drier than it is today. By the mid-Devonian years, the fossil record shows that new species of fish began to evolve with lobed fins, bones, teeth, and the ability to breath air through spiracles in the skull.

Started out as a fish, how it end up like this? (source)

Why was Tiktaalik able to wander onto land? Tiktaalik, belonging to what would come to be known as the “intermediate” phase of fish and tetrapods, possessed front fins with skeletal structures akin to a crocodile, a mobile neck, and lungs alongside gills. (Tiktaalik) Tiktaalik’s structure provides all the information necessary to understand its lifestyle. Tiktaalik’s front fins differ from the fins of other Devonian fish in that they formed an early basic arm structure, allowing it to raise itself up onto land. Most other fish at the time only had rays of bones in their fins, suited for swimming but not walking. Tiktaalik’s front fins allowed it to migrate to areas inaccessible to its competitors, increasing its chance of survival. Its mobile neck was also advantageous because it allowed Tiktaalik to orient itself in the direction of prey, especially in areas where the body is relatively fixed, like shallow water or land.

Charles Darwin theorized that simple organisms gradually evolved into more complex ones, something that can be supported by analyzing the fossil record. Fossils serve as an important foundation for understanding the history of our planet, and are often more reliable for exploring the relatedness of species than morphological similarities. 

Tiktaalik's fossil (source)

Tiktaalik’s structure is the ideal model of an intermediate evolutionary phase between fish and tetrapods. Tiktaalik’s fossil was first discovered by Neil Shubin (Your Inner Fish) and a team of paleontologists in ancient stream beds in the Nunavut Territory of the Arctic. Shubin had embarked on his journey to the Arctic in search of the missing link between sea and land animals, and Tiktaalik provided the perfect blueprint for his research. Before the unearthing of Tiktaalik, scientists had long theorized about a fossil that could fill the gaps in their knowledge, but had no such fossil to present to the evolutionary nonbelievers.

Despite the overwhelming amount of evidence supporting the theory of evolution, plenty of people still refuse to accept it as fact. Looking back in America's history, in 1925 the Scopes Monkey Trial brought up the debate of the legitimacy of Darwin's ideas. John Thomas Scopes was accused of teaching evolution in schools, which at the time was ruled to be a violation of Tennessee state law. With this trial taking place in the early nineteenth century, Tiktaalik's big break in science was yet to come, and Scopes was fined for his violation. Yet, this was far from the end.

Since Shubin’s discovery in 2004, things have started to change. Tiktaalik has been used to defend the education of evolution in schools, like during the Kitzmiller v. Dover trial in 2005. In this trial, arguers for the concept of “intelligent design,” later revealed to be a veiled concept of creationism, asserted that some organisms were simply too complex to have evolved through Darwin’s theory of evolution. The discovery and presentation of Tiktaalik during this trial was monumental in turning the decision and proving to the intelligent design team the validity of Darwin’s logic.

Remember your roots! (source)

But, why does it matter that we know where we came from, anyways? This is because knowing our history allows us to bridge a deeper connection between ourselves and the planet we inhabit, as well as the other species we share it with. Humans have a tendency of thinking about the world in terms of themselves, but evolution supports that, even if humans are the dominant species in current day, mass extinctions like the Cretaceous-Tertiary extinction are always possible--and, with the rate the Earth is warming today, many scientists even theorize we are on the brink of another mass extinction, one humans may or not live to tell the tale of.

Evolutionary biology allows us to understand the principles behind the origins and extinction of diverse species. Our Earth continues to change whether its species are aware of it or not, and if we don't keep evolving to suit these changes, we risk facing a similar end to our friends the dinosaurs.

Now for the final question: what would we REALLY be doing without Tiktaalik?

Most likely, eating plants and small fish. Definitely not writing blog posts. So, the next time you want to complain about something, don't blame life; blame Tiktaalik. Tiktaalik is the reason we have to go to school every day, and Tiktaalik is the indirect cause of millions of horrible conflicts, worldwide poverty, hunger, inequality, you name it! Do you think Devonian fish had complex enough thought to establish capitalism? Well, I guess we'll never know. At the same time, without Tiktaalik, there would be no such thing as AP Biology, so feel free to weigh the pros and cons ;) 

So, just remember-- you owe your life to this little fish! And trust me, it gets cuter the longer you look at it.