Life today always progresses from life. However, at least once in its history it had to come out of the dull thing.
Let’s face it: most of us want a family tree that will last for many generations, perhaps to the grandparents of our great-grandparents. But it couldn’t be more wonderful than that Extend that tree to our distant ancestors, I mean, to the origin of life?
In this article, we will outline some of what is currently known about one of the most exciting topics in science.
What defines life?
The first difficulty in researching the origin of life Definition Important traits to be classified as life must be unavoidable. To take a small example, this question may seem simple compared to a stone rabbit. But that is not the case when we go back to those distant times when life began.
Life today always progresses from life. However, at least once in its history it had to come out of the dull thing. No wonder the first forms of life are so similar to the inanimate things they came from, which means that it is difficult to distinguish them.
If we want to start looking for life in other worlds, it is also important to define the essential attributes of life. In particular it can be presented in a way that is indistinguishable to our eyes, accustomed to the manifestations of life on Earth.
What does life do?
Life creates its own imperfect copies, for that matter Exchanges energy and matter with the external environment Through the chemical reactions that make up the metabolism. For its proper functioning, some Instructions, Information to be maintained over time, therefore, should be passed on to offspring. In addition, a box is needed that distinguishes the lifestyle from the environment and allows proper interactions between its components.
The only example of life we know of is the landscape, The information is stored in the DNA molecule The following rules are based on the 4-letter alphabet (four nucleotides: A, T, C, G). Depending on the order in which they are regulated, they can lead to the efficiency of different proteins. These proteins facilitate life’s own chemical reactions. But there is no doubt that things could have been different. And they may even be in other parts of the universe!
When did life on earth appear?
The age of our planet is estimated to be about 4,570 million years (Ma). Initially, their temperature was too high and did not match the stability of the biological molecules. Up to about 3,850 Ma the conditions began to be stable and favorable for life.
However, they have been discovered Signs of bacterial life in rocks 3,500 Ma, Which raises the problem that there is only a period of about 350 Ma, in which everything had to happen, which facilitated the appearance of the first cells. It seems like a very short time for something so complex and exciting to come out …
To try to explain the initial appearance of life, theory panspermia, Which maintains that life was created in space from the space between the planets. Despite this paseo It seems impossible in microbes throughout the universe to find organic matter in meteorites, comets and galaxy dust clouds, and if that thing falls in the right place it could greatly accelerate the prosperity of life.
The first steps
In the early 1920s, Hypotheses of Oberin Y Haldane They argued that the first step in the origin of life was the synthesis of organic molecules in the primitive atmosphere, using the sun’s ultraviolet light as energy. Those molecules will join shallow lakes or oceans. There they will lead the call together Adi Soup, The basis for the synthesis of the most complex molecules that facilitate the origin of cellular life.
This theory greatly reinforced Stanley Miller’s famous experiment in 1953. It is no more or less than the introduction into a room, it is a mixture of gases that is believed to create a primitive atmosphere. After being energized by electrical discharges, the gases reacted and led to many basic elements of the organism, thus proving that their synthesis is possible under azotic conditions.
Miller experiment or Many others later They show that things must necessarily happen that way. What they mean Possible pathways for transition between chemistry and biology. One of them happened on our planet about 3,800 Ma.
The world of RNA
In today’s world, functional proteins are formed because the information for their synthesis is encoded in DNA. But moving from a sequence of DNA to a protein is a complex process that in turn requires the intervention of other proteins.
The separation of information and function into two different molecules presents a paradox that can be resolved by acknowledging that ancient world information and function depend on the same molecule. There is currently ample evidence that this molecule may be RNA, another nucleic acid similar to DNA, but with a single chain.
Showing that viruses and RNA viruses can use it to store hereditary information. The functional potentials of RNA are derived from its folding ability, which leads to three-dimensional structures, similar to the formation of proteins, which facilitate the catalysis of life reactions.
Call “The world of RNA“They are made up of a set of molecules capable of storing and transmitting information through their duplication. The catalytic properties of the same molecules facilitate the appearance of a simple metabolite that would have been the basis for the appearance of the first cells once customized in a box.
In an aqueous medium, fatty acid molecules can form vesicles, which may be a primitive cell. What an extraordinary thing Vesicles containing RNA molecules capable of reacting to some simple metabolic networks. They split! It’s not life yet, but it starts to look like that.
Connecting the RNA response to the segment of the vesicles is missing. Also, one of the most important is that some of them get an advantage over the rest. At that point natural selection can begin to take effect, along with all the processes that led to the increase in biological complexity and diversity.
How many failed attempts have been made to reach those first cells? We do not know that. What we have described should not be a one-time event. But what is clear is that the strength of natural selection, combined with the random environmental phenomena that led to the survival of a lineage, is the strength of that universal ancestor that unites all living things on earth. (I)