British biologists have discovered the mechanism by which life acquired the ability to stabilize the work of the Earth's ecosystems and climate, which, in turn, helped it survive for more than three billion years. Their findings were presented in the journal Trends in Ecology and Evolution.
“We discovered two simple principles that governed the evolution of life before it could transform the Earth into a system that stabilizes itself. Now we have a chance to find the answer to the main question - how and why our ancient ancestors arose,”says Tim Lenton from the University of Exeter (UK).
As the calculations of astrophysicists show, the Galaxy and the entire Universe as a whole should be teeming with life, but scientists have not yet been able to find any traces of intelligent or unreasonable aliens. Many researchers believe that this is due to the fact that life quickly appears and disappears even faster, without having time to leave significant traces.
In this case, the question arises - why did not life on Earth disappear in three billion years of its existence? The first explanation of this paradox was presented by the famous chemist James Lovelock back in 1972 in the framework of the so-called Gaia hypothesis.
She postulates that the climate and conditions on Earth are directly regulated by its inhabitants, green plants and other living organisms, just as the body of warm-blooded animals reacts to changes in ambient temperature.
This idea explains well how earthly life managed to exist for so long, but it does not answer the most important question - how did this self-sustaining system form and how did the "symbiosis" between life and the planet come about?
Lenton, one of Lovelock's most famous followers, and his colleagues attempted to find an answer to both of these questions by studying how natural selection, evolution and local stability are related.
As scientists explain, many evolutionary "innovations" can be useful for the survival of one species of microbes, animals or plants, but they can destabilize the entire ecosystem and lead to the rapid extinction of all its inhabitants by depriving them of all available resources, sharp changes in acidity or others. properties of the environment.
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A striking example of this is the appearance of the first cyanobacteria and the most powerful ice age generated by them. It arose about a billion years ago as a result of a sharp decline in CO2 levels in the atmosphere. He actually "zeroed out" the entire development of life in previous historical epochs.
If evolution proceeds in rather modest and slow steps, then life has enough time to adapt to new conditions or to changes associated with "external" factors. Their role can be volcanic eruptions, increased solar activity or changes in the circulation of rocks in the bowels of the Earth.
As Lenton notes, this "evolution of stability" is inextricably linked to the next step in the development of life - "selection for survival." In the understanding of the authors of the article, living things that destabilize ecosystems will disappear faster than other types of microbes, multicellular organisms and plants. This will ultimately lead to the formation of the fully stable and self-regulating Earth where we live today.