How did life on earth originate? What happened to the earth in the past billion years? How was the first life born?
All these questions, in a variety of disciplines, people are constantly seeking answers, but these answers are not easy to find, scientists spend a lot of effort to finally have a shallow understanding of this, then there will be a kind of biology from ancient times to the present, and can provide scientists with very favorable evidence?
Actually, there are. This is a kind of biological fossil, and it is also the oldest fossil on the earth, which is called stromatolite.
So what is stromatolite? Before introducing it, we should first introduce a concept called archaea. This kind of Archaea is also known as the oldest life on earth. After all, these bacteria appeared 3.9 billion years ago. At the same time, these Archaea also appeared naturally in the ocean. Here, we need to pay attention to the fact that these bacteria are basically in a state of no oxygen. After all, they really don’t need oxygen. Oxygen is very dangerous for them Yes.
In this case, they went on to evolve, and then they evolved a special kind of organism, called cyanobacteria, which can carry out photosynthesis just like modern plants. For example, they can capture carbon dioxide and consume it on their own, thus releasing oxygen.
In this process, it will also secrete a kind of mucus, which will connect the rest types of microorganisms together. Therefore, in the sea water, the mucus will not dissipate, and at the same time, it will combine very small minerals together. The minerals gradually stack up and finally become a kind of microbial sedimentary rock, which is called stromatolite.
Seeing this, many people may think, is this a thing built by corals? In fact, it is very similar, but corals are built by corals, but this stromatolite is built by microorganisms.
Therefore, in the field of biology, scientists believe that it is a kind of living rock. For example, these microbial species are also very complex. Sulfate reducing bacteria, sulfur oxidizing bacteria, fermenting bacteria, cyanobacteria and so on, all bacteria will continue to develop and interact with each other. For example, the metabolites of sulfur oxidizing bacteria will provide nutrients for fermenting bacteria, so the ecosystem on earth is not stable The formation of the fault.
There are about 3.6 billion microorganisms living in each square meter of these ancient fossils. At the same time, they are growing slowly, covering the old with new ones, and the number is also increasing. Therefore, the earth was in a period of negative oxygen, and oxygen can account for about one fifth of the atmosphere. At this time, this kind of rock is indispensable. After all, only sufficient oxygen can make it more effective There are many kinds of life.
At the same time, there is also evidence that makes astronomers very happy – because it is a kind of stone, so it has texture. The texture not only represents its age, but also records the information of astronomy and geography. For example, the dark lines may be related to the phototaxis of the bacteria. If it is in the daytime and the sunlight is very abundant, the cyanobacteria will grow vertically in the direction of light. During the growth process, the mucus will be secreted again, so the surrounding particles will be recycled The next gathering, if at night, it will only crawl and no longer accumulate, then it is the dark grain in the rock.
Therefore, obscure changes record the alternation of day and night and seasons. By studying these textures, scientists can infer the previous changes, especially the changes of time and seasons. For example, before 1.3 billion, the earth had 546-588 days a year, so the total months should be 13-14 months. Sure enough, according to other creatures, the results are almost the same.
According to scientific research and investigation, this kind of biological fossil reached its peak 1.3 billion years ago. After all, this kind of rock was found all over the world in this period, that is, seven continents. However, after the Cambrian, the number of this kind of rock began to decrease due to the explosion of life.
Therefore, it may become another means for scientists to judge the earth through paleontological fossils.