How life came about on the third rocky planetrevolving around an unremarkable star in the center of the solar system? People have been looking for the answer to this question throughout their history. But only in recent decades, scientists have achieved some success in understanding the mechanism of the origin of life in the oceans. It might seem that something as complex as life should be an incredibly rare phenomenon and that it probably took a long time to occur. But in 2015, scientists proved that life appeared on Earth 300 million years earlier than they thought. This means that after our planet was formed, it took only 400 million years for the first life forms to appear on it. At the same time, four hundred million years is an instant compared to 4.5 billion years of the existence of our planet.
What is needed for the emergence of life?
When scientists try to answer the questionhow life appeared on our planet, the first thing you should pay attention to is time. We know that the Earth was born 4.5 billion years ago, and the first fossil remains discovered in Western Australia are 4.1 billion years old. Does this mean that life on the third planet from the Sun was born almost immediately?
The authors of the work that was published inFive years ago, Journal Science believed that with the right ingredients, life forms very quickly. Speaking of the right ingredients, it’s important to understand that the main ingredient - at least in the case of rocky terrestrial planets - is water. And on our planet, as it turned out, water was present from the very beginning.
It should be noted that the presence of water is soIt is important for the development of life that many astronomers in search of life on other planets in the literal sense of the word “follow the water”. That's why today scientists equip missions to the icy moons of the gas giants of Europe, the satellite of Jupiter and Enceladus, the satellite of Saturn. Both satellites are covered with an ice shell, under which there is liquid water. Read more about how scientists will seek life in the solar system, read in our material.
So what did scientists discover in WesternAustralia? The find was cyanobacteria, also known as blue-green algae. Potential fossil specimens have been discovered in rocks of about 3,500 million years old. Although commonly called blue-green algae, cyanobacteria in fact, they are not algae. Cyanobacteria and bacteria in general are prokaryotic life forms. This basically means that their cells do not have organelles (tiny structures inside the cells that perform certain functions) and do not have separate nuclei - their genetic material mixes with the rest of the cell. This feature is characteristic of bacteria and archaea.
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All other life forms on Earth, includingreal algae are composed of eukaryotic cells with organelles and genetic material contained in one place (nucleus). But why bacteria, you ask? The fact is that bacteria (and archaea) are hardy creatures. They thrive in hot, cold, salty, acidic and alkaline environments in which most eukaryotes die. And prokaryotes, as you know, are the earliest forms of life on Earth. These were simple creatures that fed on the carbon compounds of the early oceans of the Earth. You can find even more articles about life forms on our planet on our channel in Google News, subscribe, do not be shy.
But over time, others have evolved.organisms that use solar energy together with compounds such as sulfides to generate their own energy. Then cyanobacteria went even further: they began to use water in the process of photosynthesis, releasing oxygen as a by-product. Over time, enough oxygen has accumulated in the Earth’s atmosphere to ensure the evolution of oxygen metabolizing organisms.
It is important to understand that the evolution of eukaryoticcell was an important milestone in the history of life on Earth. As conditions became increasingly favorable, more complex organisms developed. And so we appeared.
However, an understanding of the processes leading tothe emergence of life is complicated by biology itself. The atmosphere of the Earth today is little like the atmosphere of the early Earth, in which life developed; it was almost restored by bacteria, vegetation, and other life forms that have acted on it for many eras. Fortunately, the solar system has preserved for us many natural laboratories in which we can study the raw ingredients of life - volatile substances, organic substances, as well as chemical processes leading to life. We can also find on Earth direct evidence of the interaction of life with the environment and the changes that life has undergone as the planet develops. When we understand how life on Earth evolved, it will be much easier for us to find life beyond.