Scientists have recently found evidence of a devastating “shock” to life on Earth, which led to the emergence of a completely new form of life.
Earth once went through a period of becoming a snowball, seemingly lifeless. However, had this not occurred, our current civilization, and possibly our species, might not have emerged at all.
In a study recently published in the scientific journal Proceedings of the Royal Society B, the “Snowball Earth” during the Cryogenian period (720-635 million years ago) of the Neoproterozoic era contributed to the creation of a completely new form of life.
This new life form is multicellular organisms.
Snow-covered Earth during the Cryogenian period – (Graphic: NASA).
Why did multicellular organisms emerge? Solving this mystery could help identify life on other planets and also explain the diversity and complexity of life on Earth today.
According to Sci-News, the common belief is that oxygen concentration must reach a certain threshold for single-celled organisms to form multicellular populations.
However, the story of oxygen does not fully explain why the multicellular ancestors of animals, plants, and fungi emerged simultaneously on our planet.
Previously, life had undergone an incredibly slow evolutionary process. As earlier evidence suggests, Earth began to host life as early as the end of the Hadean eon (3.8 billion years ago), and possibly even from 4.1 billion years ago.
Yet, by the early stages of the Neoproterozoic era – around 1 billion years ago – life on Earth was still quite primitive.
Using theoretical models, researcher William Crockett from the Massachusetts Institute of Technology (MIT) and his colleagues discovered that a hypothetical primitive animal ancestor would expand in size and complexify under the pressure of a snow-covered Earth.
In contrast, a single-celled organism that moves and absorbs nutrients through diffusion, like bacteria, would become smaller.
This is because the frozen oceans during the “Snowball Earth” period blocked sunlight, reducing photosynthesis and consequently depleting nutrients in the oceans.
At that time, larger organisms could process water for food intake more quickly, thus increasing their chances of survival.
Due to this harsh survival pressure, various types of multicellular organisms emerged en masse and managed to survive through the harsh glaciation period.
As glaciers melted, these larger organisms found better conditions for expanding their populations and gradually evolved into more complex forms.
541 million years ago, Earth transitioned from the Ediacaran period of the Neoproterozoic era, marking the end of the Proterozoic eon. This was also the time when the Cambrian period began, the first period of the Paleozoic era in the Phanerozoic eon.
This transformation marked a well-known biological explosion in the Cambrian period, with complex multicellular organisms emerging, displaying bizarre shapes that laid the foundation for modern species.
However, new findings indicate that the “Snowball Earth” hundreds of millions of years before the Cambrian provided the “raw materials” for this famous biological explosion.
According to Dr. Crockett, these new research results serve as a guide for paleontologists to search for organisms that emerged during the Cryogenian period, which could provide data on the first evolutionary leap on Earth.
