Every species on the planet earth does not come to exist eventually. They change through an evolutionary chain and become the complicated forms we see today. We call it a chain to make it less complicated, but it is a web. In this web, different species share common ancestors. Just like that, there is a dinosaur in your genome.
Early ages of dinosaur genome and You
From a mixture of chemicals that turns into self-replicating molecules to single life forms, sponge-like creatures, the first life forms to have hearts, early vertebrates, fish, and amphibians, the reptiles start to dominate the planet.
These animals were cold-blooded and had scaled skins. They laid eggs. They had three-chamber hearts. Reptiles were the first to fully adopted land since they laid eggs on the land, unlike amphibians.
First reptiles emerged 320 – 310 million years ago in the later Carboniferous period. With significant changes, reptiles are still here. There are more than 10,700 species of reptiles estimated to live on earth.
Common genome ancestor with to you and dinosaur
The era we are talking about (~320 million years ago) is not properly represented in the fossil record. However, we know the first amniote had arrived in the later Carboniferous period. Amniotes are a group of vertebrates including birds, reptiles, and mammals. The first amniote be look like a lizard, but they are genetically different.
Moving on, the amniotes evolved into two groups, the synapsids, and the sauropods. Mammals and mammal-like reptiles fall into synapsids whereas other reptiles including dinosaurs are fall into sauropods. So, the last common ancestor of humans and dinosaurs should be these first amniotes.
The age dinosaurs and mammals coexisted is quite interesting. Land, sky, and water are dominated by giant reptiles. Mammals couldn’t compete with them. So, they took unique adaptations.
They all were smaller. Sometimes there were some mammals large like dogs but because of the threat of dinosaur predators, they were forced to smaller sizes. But all first mammals were not rat-like creatures. They were impressively diverse.
The world has one continent 225 million years ago. It is called Pangaea. Later on, Pangaea was divided into two separate parts. Mammals emerged in the north part but migrate to the south part. Mammals ate efficiently. Their jaws were specialized to grind and eat, unlike dinosaurs who grab and gulp. This helped them to take much nutrition as possible out of their food. So, they can survive in this very competitive environment.
Agilodocodon scansorius was the first known mammal that lived on trees. That is a clever way to avoid competition with dinosaurs. Even though some evidence suggests some dinosaur species lived on trees, there were not any widespread species like that. Some mammals choose the sky to roam. They were like modern-day flying squirrels. But studies of their fossils uncovered they were capable of forced flight. If that is the case, instead of flying squirrels they should be similar to modern bats. There are traces of them in aquatic areas which suggest an early aquatic mammal life.
Mammals had fur-covered bodies. Their eyesights were less accurate and only could see a limited number of colors. All these adaptations were helpful to living in a cold environment and being active at the night.
Mass extinction of dinosaurs
Dinosaurs along with most reptiles were extinct by an asteroid that crashed on the earth 66 million years ago (At the end of the Cretaceous period). Mammals were able to survive by taking shelter underground. While an electrically charged ejecta cloud cover the earth and giant reptiles were dead out, mammals were surviving and ready to take over the world soon.
Because of the competition with dinosaurs, we mammals had superior adaptations. With the competition gone for good, they got the best evolutionary opportunity they ever had. So, mammals were able to evolve into complex forms. They survived several mass extinctions and today live on land, sky, and water.
Your genome has dinosaurs
Later on, mammals that lived on trees evolved into different species and made the group primates. The most interesting thing about them is the ability to use their hand to do complex things. And you (modern human) are the most unique primate with the highest intelligence on the planet and not to mention incredible running abilities.
There are a few traits that humans(mammals) and dinosaurs (Reptiles) have in common. Both of us and birds undergo embryonic or fetal development within an amnion. They share 90% nucleotide sequence identity with classical mammals.
The most significant similarity comes from Jumping DNA. Jumping DNA is a special DNA sequence known as transposons. They can move through the genome and copy themselves elsewhere. For the first time, we have now sequenced a dinosaur (Reptile) genome in your genome. They are not compulsory for us. But they can provide great agility and resilience in dealing with unexpected environmental challenges.
The human brain and reptile brains have some similarities. We know both of them evolved from fish. So have some parts of the brain inherited from fish. They control basic functions like breathing, coordination, and balance. Also, they take a part in primary survival strategies like feeding, mating, and defense. It makes sense because fish only had to do those things. But while evolving reptile brains changed a lot.
Both human and reptile brains are capable of processing emotions. Human emotions are more complex than reptiles but still, both of them have emotions. So, with all this, we can conclude. The dinosaur in your genome handles basic functions and survival skills while the mammal handles your memory and emotions.
Evolution is an incredible process. The existence of you is proof of it. The adaptation we took to coexist with dinosaurs helped mammals to survive through mass extinction events and decorate today’s life on earth. We don’t know how long mammals will exist on the planet or what would they become in million years of the future. But we do know who they are and where they came from.
I hope this article will help you to understand the dinosaur in your genome. Stay with us for more interesting topics like this.