This should have been an exciting time for the Earth.

All the ingredients of the modern world were in place. We had oxygenic photosynthesis. We had the three domains of life: bacteria, archaea and eukaryotes. Seriously, all the ingredients were there. There should have been nothing stopping evolution from running rampant and for complex multicellular lifeforms to appear.

But instead… nothing happened.

Everything was put on pause.

The period from 1.8bya to 0.8bya has been called 'the Boring Billion' and "the dullest time in Earth's history."

Of course, it is a tad harsh to say that nothing happened. As we will see, there were important evolutionary developments, but they were understated.

So, what went wrong? Why didn't we see the rapid evolution of eukaryotes into the complex life that we have today?

Well, for 300 million years, the Earth's tectonic plates had been moving towards each other. And, then, around 1.8bya, they merged to form the supercontinent of Columbia. Around 1.5bya, Columbia began to tear apart. But it never properly fragmented. Instead, it reunited as a new supercontinent, Rodinia, which did not split apart until 750mya.

So, from 1.8bya to 750mya, the world consisted of one huge continent.

And that has consequences.

It meant that there was one deep ocean. This was not conducive to evolution, which preferred sunlit coastal waters.

But the extent of the sunlit coastal waters was limited by the fact that there was only one coastline.

And the coastal sunlit waters that did exist were already full of prokaryotes.

The sad truth is that, in the Boring Billion, the eukaryotes could not compete with the bacteria and archaea.

Of course, they were not helped by the low levels of oxygen in the atmosphere and the surface waters.

But, perhaps even more importantly, they were hindered by a lack of available nutrients.

Why was this?

Well, because there was no tectonic movement, there were no mountains. No mountains meant no erosion, which meant fewer nutrients washed into the sea.

And this was a fundamental problem. Because eukaryotes need a whole range of trace elements, such as phosphorus and molybdenum, to form certain key enzymes.

It's chemistry, innit?

The eukaryotes could not evolve because they lacked certain essential lego pieces.

Not only that, but both Columbia and (particularly) Rodinia straddled the equator, which meant that there was basically a single world climate.

As we have said before, evolution is driven by a changing environment. If the environment isn't changing, then there is minimal evolution.

But, despite all that, it would be wrong to think of this period as a billion-year Sunday afternoon.

Things did happen. Preparatory things. This period was more like an assassin waiting patiently for the right moment to strike.

It's just that it took a billion years to reach that moment.

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Lovely conditions this morning

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