About 3.6 billion years ago, the first living cells arose.
About 600 million years ago, multicellular plants were born.
Slightly later, about 550 to 570 million years ago, multicellular animals began to appear.
It took 3 billion years for life to evolve from unicellular to multicellular, and then the evolution of life began to accelerate.
What made it take 3 billion years for life to move from single-celled life to multicellular life?
Why can life move from single-cell to multi-cell, and how did they move from single-cell to multi-cell?
The only clues that humans can obtain are fossils that are similar to a few words, and we will never know the whole process.
The only thing we can do is guess and try to prove it experimentally.
Miller–Urey experiment
In 1824, the German chemist Friedrich Willer tried to synthesize a new chemical substance in the laboratory. The experimental results exceeded his expectations. The white crystals produced at the bottom of the flask looked a little strange.
It wasn’t until 1828 that Wheeler knew what the white crystals were, and it turned out that it was urea.
Since we can make urea out of nothing, is life also in this form out of nothing?
128 years later, in 1952, inspired by this idea, Stanley Miller persuaded his mentor Harold Urey to perform the famous Flask of Life experiment.
Miller simulated the environment of the ancient earth, prepared a large flask, filled it with water, simulated the ocean of the ancient earth, and then heated the bottom of the flask, because the temperature of the ancient earth was very high, he filled the flask with gas, including methane , ammonia, hydrogen, simulate the atmosphere of the ancient earth, and finally, he electrified the flask to produce electric sparks, simulating the lightning of the ancient earth.
Just one day after the experiment began, the water was no longer clear, and new material was apparently produced.
A week later, Miller opened the flask and tested the ingredients in the seawater. The results were shocking. There were many amino acids in the flask.
The amino acids needed for life were born out of nothing.
Since the birth of the substances needed for life is born out of nothing, and it is generated in random collisions, then, is the evolution of life also bumped out of such random headless collisions? Otherwise, why did it take 3 billion years for unicellular to multicellular life?
If they weren’t random ramblings, but directional, would it take so long?
Cellular automaton:Game of life
In 1970, British mathematician John Horton Conway invented the cellular automaton.
To be precise, cellular automata is a mathematical game.
In this life game, assuming that the current life is a single cell, for any cell, its rules are as follows.
The universe of the Game of Life is an infinite, two-dimensional orthogonal grid of square cells, each of which is in one of two possible states, live or dead (or populated and unpopulated, respectively). Every cell interacts with its eight neighbours, which are the cells that are horizontally, vertically, or diagonally adjacent. At each step in time, the following transitions occur:
- Any live cell with fewer than two live neighbours dies, as if by underpopulation.
- Any live cell with two or three live neighbours lives on to the next generation.
- Any live cell with more than three live neighbours dies, as if by overpopulation.
- Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.
The rules of this game of life invented by Conway are so simple that this game is extremely suitable for computer programs to implement, because computers can perform more random and unlimited number of crash tests, and get results quickly, giving us the opportunity to have a glimpse possible answer to the question “How did unicellular life evolve into multicellular life?”
After completing multiple rounds of random and unlimited number of collision tests on the computer, these single-cell automata have evolved into amazing multi-cellular automata, and formed different types, either static or dynamic, or Move, let people sigh how similar this is to multicellular life 600 million years ago.
The first multicellular automaton is the following steady state, which makes it seem like a quiet multicellular plant:
The second type of multicellular automaton is the following oscillation state, which makes people feel that life is beginning to evolve from static to dynamic:
And a third type of multicellular automaton, which is able to move, feels as if life burst out of the computer program:
In the end, unexpectedly, we simulated the birth and evolution of life by computer.
Or to be more precise, because life itself is a computer, it is possible for us to simulate it in a computer. Otherwise, we may never know the answer to the birth and evolution of life.
Once again, I was shocked by this computer of life. Although the birth and evolution of life are so random, the rules are always there. No matter how simple the rules are, as long as there are rules, life can be tenacious and indomitable will, ramming without direction until it hits its own direction.
After that, the evolution of life began to speed up, all the way forward!