hey there!  welcome to the new episode of Curiosity! A series in which we will answer some of the questions that makes us all curious.   

Earth is estimated to be 4.5 billion years old and has been home for various species till now but chances are you might have never even thought of how the first single celled life originated on Earth. No, it was not Aliens. It certainly was Science. This is what we are gonna discuss today so Lets get right into it.

Scientists have found some of the oldest evidences of life in the form of  fossilized mats of Cyanobacteria. They are called  stromatolites in Greenland and are estimated to be 3.7 billion years old. They can be still found today and have a very complex form of life. They have their own complex cell wall protecting the DNA. But despite of these discovery, scientists are still confused , how did life really originate on Earth. There are actually many theories. Well the Most accepted theory is given by Stanley Miller , which i will describe in this article.

How did Life Begin On Earth?

Scientists do know the composition of Early atmosphere on Earth and certainly was very different from our present atmosphere. Earth's Ocean at that time was filled with lots of minerals. So the idea is , ocean already contained all the things that are necessary to make RNA and these RNA started chemically reacting with something and started creating all life on Earth.

Fig :Urey and Miller Experiment (Credits)

So , in 1952 Stanley Miller and Urey designed an experiment with all the necessary atmospheric conditions of the early atmosphere to see how the complex single celled might have formed on Earth. The compositions of Early atmosphere on Earth were  Ammonia, Methane, Hydrogen and Water Vapor. The experiment was quite simple.They put in water to mimic the ancient ocean and was boiled to show evaporation. They sealed all these compositions in a special air tight container and simulated the lighting of Early Earth by sparks of Electricity for a week.

By the end of the week , they observed , a reddish brown substance has coated the walls of the container. That reddish brown substance contained 11 - 20 amino acids , that are believed to be present on Early life of Earth. This was a breakthrough finding and since have been confirmed by many scientist with similar results.

The goal of the Experiment was not to create a life but to see if the simple chemistry can form the complex molecules essential of life.

Formation of Self Assembly Molecules

In the Early Earth , Heat acted as the catalyst for formation of polymers from simplest forms.Scientist have shown that when the simple organic molecules are heated , the water vaporizes and links the simple molecules into polymers. They are called Proteinoids.

Fig : Proteinoids (Credits)

It is believed that, the Early polymers formed on Earth could spontaneously self assemble  and form droplets that enclosed a watery solution and maintained a proper chemical environment. These spheres were called protobionts.

These membrane bound protoionts could perform similar functions as of modern cells like dividing when they reach to certain limit,and responding to hypo tonic and hyper tonic solutions.

Conclusion

The formation of the first living cell was the series of  a very complex chemical reactions and processes. The separate formation of monomers, polymers, organic compounds , protenoids and protobionts led to the formation of first primitive cell. They later evolved and form various microscopic structures like cell organelles and made a cell independent and allowed to perform variety of functions necessary for life.

 That's it for this Episode guys, Hope you enjoyed it. If you did, Upvote and comment your thoughts below. Thank you

Stay Curious.

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Last Five Episodes:

 Curiosity | What Happens when you go into Coma?

 Curiosity | Why do some people Sleep Walk?

 Curiosity | What is the possibility of being hit by an Asteroid?

 Curiosity #36 | Can Freezing our body make us Immortal? 

Curiosity #35 | What Would happen If all the humans suddenly disappeared overnight?