When it comes to the evolution of the earth, the cyanobacteria that appeared on the earth 3.5 billion years ago played a very important role in both the earth’s climate and the environment, and in life on the earth. The emergence of cyanobacteria changed the structure of the earth’s atmosphere, absorbing a large amount of carbon dioxide, and producing a large amount of oxygen through photosynthesis of cyanobacteria. The oldest anaerobic organisms on the earth became extinct, and life on the earth entered the aerobic stage.
However, when many people mistakenly believe that cyanobacteria are plants, in fact, cyanobacteria are microorganisms. So, how did the earliest plants on the earth appear?
Researchers said that the earliest plants appeared about 2.5 billion years ago. Their forms were mainly algae and fungi. However, they were not the direct ancestors of land plants. What does this mean? Simply put, there were no plants on land for a long time after the appearance of plants. It was not until more than 400 million years ago that great changes took place on the earth.
440 million years ago, the earth entered the Silurian period. The Silurian period existed on the earth for a total of 30 million years, but it was closely related to the evolution of life on earth.
Before the Silurian period, the ocean area on the earth was much larger than it is now. Later, with the geological movement, the ocean area began to shrink and the land area continued to expand. At this time, the creatures on the earth also ushered in a new opportunity for evolution.
In the late Silurian period, some marine organisms began to evolve in the direction of land organisms, such as the earliest amphibians and the earliest land plants.
Through fossil research, the direct ancestors of land plants came from the naked ferns at the end of the Silurian period, which later evolved into ferns and gymnosperms respectively.
Gymnosperms are the ancestors of angiosperms. They began to evolve in the Jurassic period. After the vigorous development in the Cretaceous period, flowers and various edible plants appeared on the earth.
So, how did plants evolve from generation to generation? In the process of studying this issue, some time ago, scientists from the UK discovered that when plants reproduce sexually, they can pass on their “memory” to the next generation, and the quality of “memory” directly affects the survival rate of the next generation.
Today, the plant kingdom on Earth is basically dominated by angiosperms. When scientists study botany, many experimental samples are also angiosperms. For example, Arabidopsis thaliana has always been a “net celebrity” in the field of botany due to its strong adaptability, fast reproduction speed and short growth cycle.
Some time ago, in the process of studying Arabidopsis, researchers found that after sexual reproduction, Arabidopsis will pass on its two proteins to its offspring, and these two proteins are closely related to their growth and development. In other words, if the previous generation of Arabidopsis develops well, then the offspring will inherit its “memory” and develop as fast as it, and the survival rate is extremely high. Otherwise, it will be dysplastic.