The Precambrian (which includes the Archean Proterozoic) took more than 2/3 of the time that life has been on Earth.
The entire rest of life is in that last green box. Visit the ChronoZoom site.
Life emerged into the world completely blind, its movement through the oceans determined by the constant ebb and flow of waves and tides. It was pushed in and out, rolled and turned in crashing waves, or sunk deep beneath the surface. Life felt night and day through slight differences in the temperature of the water. It sailed through the red nutrient rich oceans, surrounded by all the food it needed to replicate. It picked them out of the water when they were needed, and divided in two.
Life multiplied throughout the ocean, and until it filtered throughout every inch of the waves, down to the floor of the ocean. It moved with the ocean, and consumed and transformed it. Everywhere it drifted it bloomed, restructuring particles of the ocean into more Life. As it bloomed, it rejoiced at the ease of replication. Throughout the billions of new particles of Life, particles that were compelled to gather and replicate faster than the others edged out the others. Slowly, Life developed a dull ache of hunger for food to replicate that became more pronounced through its generations, alleviated only by more consumption and replication. It was compelled towards food, and strove to immerse itself in and fill new areas.
The process of replication was not perfect; mistakes in the assembly meant that some of the copies were different from the original. Sometimes they copied more accurately, or less so, or copied faster, or less so. Ones that could copy faster eventually overshadowed the others. But the molecules were also fragile. Too much heat, or too little could be disastrous, as could being too close to certain kinds of chemicals, which could react with and destroy them. Very, very slowly, molecules of this family emerged that could not only replicate, but also create chemical walls around themselves to protect from hostile environments. They proved to be successful, and became progressively more advanced. Then, later cells could create structures inside this wall to aid in gathering resources for replication. These also proved to be successful, and also became progressively more advanced. Each tiny progression took longer than the lifetime of a civilization. Eventually, these molecules could be called 'cells' [why?].
Nutrients were readily available in the clay-red seas. Cells fed on complex molecules known as amino acids and sugars that surrounded them in the water. They left carbon dioxide and methane behind as waste. Others developed methods of working together. Generation by generation, life branched out in every direction for resources and chances of replication. Life that was successful begat more successful life, which built on the adaptions of their ancestors in the ultimate competition for resources and replication. Cells that did not replicate went extinct.
[There is so much to fill in here. Including the cells that eat dead cells, the ones that photosynthesize (which then formed colonies away from the vents), the ones that harness oxygen and the ones that eat others. Then there are the ones who invented sex. Then the Eucaryotes. And finally there are the ones who combined to be multicellular.]
Cells that could sense the environment could better gather food, and thus better replicate. The capacity to feel was engraved onto the soul of life early in its conception. Cells may have been able to feel different concentrations of mixtures in the oceans around them, and thus strive towards food, and away from whatever may bring harm.
Snowball earth. The biggest ice age that the world has ever seen. Ice probably extended from pole to pole. The seas were frozen over. The ice was over 1km thick, like three skyscrapers stacked on top of each other [verification needed on average height of a skyscraper]. These conditions probably lasted for millions of years. Life was nearly annihilated. But extremophiles prevailed. They hung on for millions of years, conditioning themselves environments of scarcity and extreme conditions. Then the conditions got more favorable as the Earth began to warm due to volcanoes and their carbon dioxide. Nutrient rich water from the glaciers flooded the oceans. Life exploded. The oxygen catastrophe may have happened here, rather than beforehand.
[Sometimes their genes were combined, so that when one cell replicates, the others will do so too so that they will form a unit of cells, that was successful like them. But they were still susceptible to errors in replication, so variations were produced. These variations exploited even more avenues of exploitation and replication, and complexity grew. ]
One kind of these groups of cells developed a way of creating variations even faster, while minimizing 'bad' variations. If molecules from two groups that have been proven able to survive and gather resources mix together to form one original molecule, much variation is possible while lowering the chance of getting a gene that reduces reproduction, since the parents have already proved to be successful. Some forms of life thus became more complex, while others evolved in more basic ways. This development was called 'sexual reproduction' by much more advanced life in their language.
The further allocation of tasks to cells in the body turned out to be successful by some of the molecules that were practicing it. Organs developed in some, which allowed some life to become even more successful, and relationships between the life and its environment, including with other life, became more complicated.
Development of rudimentary emotion.
Memories of the era:
- Chemical and molecule-based
[What is the story that repeats itself a thousand times over during this era?]
[Finish up chapter at the Threshold for the adventure - multicellular.]
A worm-like fish. An ocean of abundance. Early in the stage of the plants/animal schism..