"The Origins of Life on Earth , Unraveling the Mystery of Our Beginning"

 "Transforming Concept Of Evolution" 

How did the first living thing on earth become a living thing? Was it a divine power that breathed life into it? Or was it an alien that came to earth to live? And after observing for a few weeks, he saw something very surprising. This is where the single cellular organism was born, which later became living beings. Life did not start on earth, but in space.

Hello, friends. Do you know that your DNA is 60% similar to a banana's DNA? No, I'm not kidding. This is true because humans and bananas had the same ancestor if you go back in time.

That is, we and a banana, which was per per per per per per per hundred millionth per dada, were the same. In fact, this is not just for bananas, but for every animal and plant in the world. And if you go back in time, if you go back even further, if you go back 3.7 billion years, you will find that all the living organisms on earth had the same common ancestor.

Luca. The full form of the name we gave Luca is Last Universal Common Ancestor. It was a single-celled organism which you can call a microbe, according to scientists.

It liked to live in hot places. And all the living things on earth today, whether it's plants, animals, fungus, algae, or bacteria, we all evolved from this one organism. It's not that Luca was the first living organism to live on earth.

There must have been many living organisms before this. But scientists don't know how they looked. In fact, scientists don't even know how Luca looked.

But the fact that Luca was a living organism is important. Because this raises the question of how Luca came to life. How did the first living thing on earth become a living thing? Was it a divine power that gave life to it? Or was it an alien that came to earth to live? This is the question of the origin of life. After all, non-living matter, rocks, soil, water, and some elements—how can they change into living organisms? Let's understand this mystery in depth in today's article.

This is my fifth article, friends, in the evolution series. Before this, I have written four more articles that you can watch on the screen. The first one is on the theory of evolution.

In the second one, we talked about how humans evolved from monkeys. In the third one, we talked about whether the chicken or the egg came first. In the fourth one, we talked about how the earth was formed in the solar system.

And in the fifth one, we'll talk about how living beings evolved from non-living things. This seems unbelievable to hear. How is this possible? Up to 200 years ago, most scientists thought so.

Most scientists believed that there is a life force present in every living being that keeps them alive. But in the 1780s, a French chemist, Anthony Lavoisier, did the first experiment that proved that perhaps living things are not so different from non-living things. He took a guinea pig and measured its body heat.

He saw how fast the ice melts due to the body heat of the animal. And at the same time, how much carbon dioxide it releases. Then he measured it with a piece of coal which would release the same amount of carbon dioxide, and the ice would melt as much as the animal.

He concluded that life is a chemical process. Non-living things and living things both work on the same chemical principles. A few years later, in the 1790s, an Italian doctor, Luigi Galvani, was working with some dead frogs.

He had hung the legs of the frogs on a brass hook, and he had a steel blade in his hand. He accidentally touched the legs, and the legs started shaking. Seeing the legs of the dead frogs shaking, he thought that he had invented the life force.

He named it Animal Electricity. He said that it's some kind of electricity which is present in every living thing, and that's why it's happening. But his conclusion was disproved by Alessandro Volta.

He said that it's not because of the legs of the frogs but because of these two metals. When the steel blade hits the brass hook, electricity is produced, and a reaction is seen in between. Later, Volta used the same principle to make the world's first electric battery.

The cells that we use, which have a voltage, the word Voltage comes from the name Volta. But still, most people were not convinced. They still thought that there is some special energy in living things which is not there in non-living things.

Actually, there was a big reason behind the scientists' thinking. Most of the chemical compounds found in a living being, like fats, proteins, and sugars, were not found in any non-living thing. Like stones, soil, and other minerals.

By the way, this is where Organic Chemistry was born. Do you remember Organic Chemistry and Inorganic Chemistry in school? Have you ever wondered why these two names are different? Because most of the organic compounds are found in humans and living beings.

And most of the inorganic compounds are found in non-living things. That's why the scientists named them Organic Compounds. And the scientists thought that these Organic Compounds were formed only in living things. This means that there is some life force which is making these Organic Compounds.

The turning point of solving this mystery came in 1828. When German chemist Friedrich Wöhler made an Organic Compound from an Inorganic Compound. He synthesized Urea from Ammonium Cyanate.

The same compound which is found in our urine. This experiment shocked everyone. For the first time, people were surprised that an Inorganic Compound can turn into something which is also found in the human body.

From here, the concept of life force started fading away. In the 1850s, a chemist living in Paris, Marceline Berthelot, started a total synthesis program. She said that only with the help of Carbon, Hydrogen, Oxygen, and Nitrogen, she could make all the Organic Compounds. And she did it.

First, she made Hydrocarbons. Then she converted Hydrocarbons into Alcohol. Then she made Esters. And then she made Organic Acids. All these things you see in the 11th and 12th Class. At this point, people started believing that Organic Compounds can be made with a chemical reaction.

But Organic Compounds don't have life in them. So where is that life coming from? For this, it is important to define life. What does it mean to be living? Does being alive mean that you can walk? If yes, then by this definition, all animals are living beings.

But trees and plants can't walk. But it doesn't mean that they are not living beings. If we say that life means things that can reproduce, then plants, animals, bacteria, etc. But what about animals like mules that can't reproduce themselves? They are alive, living things, but the definition of reproduction doesn't fit them.

The turning point of solving this mystery came in 1828. When German chemist Friedrich Wöhler made an Organic Compound from an Inorganic Compound. He synthesized Urea from Ammonium Cyanate.

The same compound which is found in our urine. This experiment shocked everyone. For the first time, people were surprised that an Inorganic Compound can turn into something which is also found in the human body.

From here, the concept of life force started fading away. In the 1850s, a chemist living in Paris, Marceline Berthelot, started a total synthesis program. She said that only with the help of Carbon, Hydrogen, Oxygen, and Nitrogen, she could make all the Organic Compounds. And she did it.

First, she made Hydrocarbons. Then she converted Hydrocarbons into Alcohol. Then she made Esters. And then she made Organic Acids. All these things you see in the 11th and 12th Class. At this point, people started believing that Organic Compounds can be made with a chemical reaction.

But Organic Compounds don't have life in them. So where is that life coming from? For this, it is important to define life. What does it mean to be living? Does being alive mean that you can walk? If yes, then by this definition, all animals are living beings.

But trees and plants can't walk. But it doesn't mean that they are not living beings. If we say that life means things that can reproduce, then plants, animals, bacteria, etc. But what about animals like mules that can't reproduce themselves? They are alive, living things, but the definition of reproduction doesn't fit them.

In 2011, Biophysicist Edward Trifonov tried to find the definitions of life. He found 123 different definitions. Among all these definitions, there was a common consensus that life is self-reproduction with variation. In this definition, creatures were added that are born from reproduction but can't reproduce themselves.

But instead of simplifying things, we need to understand the differences if we want to answer this mystery about how non-living things turn into living things. The first difference is complexity. Among living beings, there are many chemical compounds. Non-living things don't have that much complexity.

The second difference is metabolism. Every living thing needs food for energy. All animals eat food to produce energy. All trees and plants eat sunlight to produce energy. And microbes like bacteria and viruses also take something from the environment to produce energy. And the remaining energy is reused in the environment. This is called metabolism.

Metabolism is seen in everything. The third difference is boundary. Living organisms are separated from the environment around them. Our skin cells create a barrier in the environment. Their cells work in trees and plants. In bacteria and viruses, in single-celled organisms, the cell wall works. Everything inside needs to be protected from everything outside.

The fourth difference is reproduction. We can simplify it to replication. Even the smallest single-celled microbes can replicate themselves. The DNA in them can replicate to produce more of them.

Based on these four criteria, let's understand one by one how such life forms are created that meet these criteria. The truth is that the transition from non-living to living didn't happen suddenly. It happened gradually like a spectrum. It's difficult to pinpoint a point on this spectrum. But gradually, non-living things started to transform into living.

First is complexity. How did complex things like DNA form? I explained in this video how our solar system was a cloud of dust and soil from which the sun was formed and the earth was formed. After the formation of the earth, we talked about how in the beginning, there were eruptions on the earth of comets and meteors. This era is called the Late Heavy Bombardment. Some scientists believe that the building blocks of our life came from these comets and meteors.

This theory is called the Pan-Spermia Theory. According to it, life didn't start on earth but in space. It sounds weird, but today we have solid evidence that the building blocks of life are in space.

We know this with the help of spectroscopy. I explained it in detail in this video. The spectrum of light coming from billions of miles away is analyzed to find the chemical composition.

In the 1930s, with the help of spectroscopy, when scientists studied the clouds of gas and dust in our galaxy, they found complex molecules in them. In the beginning, simple molecules like methylene and cyanide were discovered. Later, as such telescopes became more advanced—radio and infrared telescopes—we found that molecules of ammonia, water, and formaldehyde were also present in space.

In 1969, in the Murchison meteorite, more than 20 amino acids were found. After that, scientists also discovered urea, glycine, and ethanol in space. When ethanol, i.e., alcohol, was discovered in space, it became a headline in the media under the name Space Vodka.

In 2014, molecules like isopropyl cyanide were also discovered. This is due to the complexity of amino acids. The Sagittarius B2 cloud, which is 25,000 light-years away from the Earth, contained molecules that showed chirality. Chirality is also a concept that you must have studied in school, where molecules have a mirror image showing left-handedness and right-handedness.

Chirality is a basic identity because amino acids are also found in DNA and RNA. There are about 20 amino acids found in every life form on Earth. They are like the building blocks of life, and all these 20 amino acids have already been found in space.

Apart from these, two types of nucleic acids—DNA and RNA—are also considered building blocks of life. Although we have not found DNA and RNA in space, we have found their building blocks. The core component of DNA and RNA is a sugar called ribose.

25,000 light-years away, in a gas cloud like Sagittarius B2, we found sugar glycol aldehyde, which reacts with carbon compounds and forms ribose. So the building blocks of DNA and RNA are already found in space. Scientist James Lovelock said that the universe is like a big warehouse where all the spare parts for life are available.

Today, most scientists believe that space itself is working like a chemical factory. This means that the Earth has to synthesize more complex molecules. In the solar system, meteors and comets have already delivered many complex molecules.

How did these raw materials form more complex things on Earth? This is the Primordial Soup Hypothesis. According to this theory, there must have been a rich mixture of these organic molecules in a hot pond on Earth, with electricity and heat from volcanoes giving life a kickstart.

In the right place, at the right time, billions of volts of electricity triggered a chain of improbable coincidences to create the first-ever cell. Charles Darwin said in 1871 that in a hot, small pond, ammonia, phosphates, electricity, light, and heat must have first formed some kind of protein.

Read This Also;- Replicating Evolution ; Scientists Fast Tracked Multicey Life In Lab.

Life must have evolved from that protein. But can this really happen? A practical experiment was done in 1953 by Stanley Miller and Harold Urey. They took a 5-liter glass container filled with ammonia gas, methane gas, and water vapor.

They put sparks of electricity in this glass container, mimicking the conditions on Earth 4 billion years ago. After observing for a few weeks, they saw something very surprising. Countless inorganic compounds were forming building blocks. A few weeks later, amino acids and carbon compounds were formed in this container.

This proved that if we have the right raw materials and conditions, the building blocks of life start forming on their own. The second criterion is replication. There is a theory for this called the Clay Mineral Hypothesis.

The four surfaces of the clay combine the primary organic molecules and increase the speed of the reactions between them. This clay provides a surface on which the organic molecules keep accumulating and concentrating. This clay was helpful in connecting nucleotide molecules, and they started joining in a chain.

Slowly, it is believed that a big chain of organic molecules was formed, which we call RNA. RNA could store genetic information and self-replicate. Once again, this has been proved by a practical experiment that small particles work on the surfaces of the clay and mix with each other to form a platform for molecular assembly.

However, it is still a mystery how the first RNA molecule formed on its own and self-replicated. But some practical experiments related to this have been done to clear some specific things. For example, in 2009, John Sutherland conducted an experiment.

He observed that hydrogen cyanide, acetylene, and phosphate—such simple molecules—could form RNA nucleotides. Here, we talk about the RNA World Hypothesis, according to which RNA was the first to form proteins and then DNA. Because RNA has the ability to self-replicate, it multiplied, evolved, and eventually became capable of forming strong, stable proteins. From these proteins, DNA was formed.

DNA could store genetic information for a long time and could make its own copies. The third criterion here is the boundary. Molecules and RNAs were forming, but when did they become separate organisms? When did they start separating from the surrounding environment?

It is not so difficult to imagine because a practical example of this can be seen at home. Whenever you go to the bathroom to wash your hands, the soap molecules come and stick to the dirt and dust on your hands and get washed away.

Why does this happen? Because it is the property of fatty acids. As you studied in school, soap molecules have a hydrophilic part and a hydrophobic part.

The part of the molecule that is attracted to water and the part that wants to stay away from water. Because of this, a shape is formed that traps oil, dust, and dirt molecules. If we look at it in a way, it is a structure of a cell, where nothing outside can enter.

The part of the molecule that is attracted to water and the part that wants to stay away from water. Because of this, a shape is formed that traps oil, dust, and dirt molecules. If we look at it in a way, it is a structure of a cell where nothing outside can enter.

These fatty acids form lipids, and when they go into water, the lipids start forming small bubbles. In these bubbles, chemicals start getting trapped inside, and these lipids start forming like primitive cell membranes. From these lipids, RNA molecules get trapped and form a boundary through which RNA lipids get trapped inside.

The structure of RNA molecules inside a cell membrane reminds you of a cell. That's why they are called protocells. Protocells mean the cells that existed before the arrival of cells.

These were the simplest forms of cells, and they evolved from protocells when they became more complex. This is where single-cellular organisms were born, which later evolved into living beings. But the fourth criterion is still there.

Metabolism. How did metabolism start? What was the need? The simple answer is energy. If we want to replicate RNA and DNA, we need energy.

In the beginning, these protocells got this energy from the Earth's environment. At the depths of the ocean, there are vents on the ocean floor which are called hydrothermal vents. A lot of warm water comes out of these vents. Scientists believe that life started here. This is called the hydrothermal vent theory. According to this theory, life started with these hydrothermal vents.

It is believed that Luca was also born here. To survive, protocells needed energy. The nutrients in the water were trapped inside.

These nutrients were trapped with the help of fatty acids. The nutrients needed to make amino acids, lipids, RNA, and DNA were used. The rest of the nutrients were simply left in the environment.

This became a simple metabolism. The energy was coming from the heat in the water. As life increased, competition started at the level of single cells.

The hydrothermal vents had a good environment. There were a lot of nutrients in the water. The water was mineral-rich.

The heat was also there to make reactions. But as soon as a cell goes away from these vents, it will get nothing. The only source of energy was to eat other cells.

Or to cooperate with them and merge with them. These two things are still seen in animals today. The first is predation.

Eating other animals to get energy. The second is mutualism. Cooperating with other living beings and working together.

An example of this is a honeybee. It drinks honey from flowers. It also helps pollinate flowers.

At the level of cells, we saw the same thing. There are four names to understand. The first is Prokaryotes. The second is Bacteria. The third is Archaea. The fourth is Eukaryotes.

Prokaryotes are single-cell organisms. They are of two types. One is Bacteria and the other is Archaea.

These two forms of life originate in different ways. But they originate from the same primordial soup. That's why they have one-third similarities. The second category of Eukaryotes are multicellular organisms, like plants and animals. Two billion years ago, there was a population of Archaea and a population of Bacteria.

These two populations lived close together. This was a mutually beneficial relationship because Bacteria used to feed on Archaea's waste. The closer Bacteria lived, the more Archaea benefited.

At one point, Bacteria came so close to an Archaea that it entered it. Bacteria tolerated this because it didn't see any harm in it. And when this happened, the second cell in one cell was able to maintain its independence.

This cell is considered an ancestor of all multicellular organisms. All the complex life on Earth—trees, plants, animals—are all from this single-celled organism. This is possible due to the merger of Bacteria and Archaea. In the 1960s, an American biologist, Lynn Margulis, did research on mitochondria that exist in cells. The function of mitochondria is to metabolize itself, providing energy to the cell.

When he studied DNA, he found that the cell had separate DNA and the mitochondria had separate DNA. Mitochondria's DNA is similar to the DNA of a bacteria called Typhus, which causes fever, headache, and rash in humans. The conclusion from this is that the mitochondria and the remaining cell must have been two different organisms at one point in time.

Today, there is solid evidence that the merger of Archaea and Bacteria resulted in the formation of Bacteria mitochondria and Archaea the remaining cell. And because mitochondria exist only in eukaryotes and not in prokaryotes, all the multicellular organisms were born because of this. Without mitochondria, no multicellular organism was possible.

All eukaryotes require a lot of energy to stay alive. And only mitochondria provides. A healthy eukaryote can support a genome 2 lakh times bigger than a bacteria genome and can command 2 lakh times more energy. Due to this extra energy, eukaryotic cells were formed and genes were started.

And the process of natural selection started. So, overall, this transformation from non-living thing to living being is not something that happened in a jiffy. A lot of different things have happened for this, which took a long time.

Specifically, it took at least 2 billion years for this transformation to happen. The first age of life is estimated from 3.7 billion to 4 billion years ago. And the age of a multicellular organism is estimated at least 1.5 billion years ago.

It takes a long time, and a lot of different processes have to be perfected with the right conditions and raw materials for this transformation to happen. But it's not wrong to say that we all are made of stardust. All the things we want to be are present in space.