The history of life

The same milestones, cut differently: only those the corpus files under life or evolution. Thirty-seven of them, from the last common ancestor of everything alive to the genome we now edit. What this page shows is not a lineage — no tree here, and no descent. It shows when each thing was invented, and how long the gaps between the inventions are: two billion years between the first cell and the first nucleus, half a billion between the first animals and the first flower. The gaps are the point, and only a timeline shows them.

37 milestones out of 200, in 10 chapters

Hadean4.54 Ga → 4.03 Ga

Five hundred million years without a single rock left to show for them. The eon takes its name from the underworld, and it is the only division of Earth's history defined by the absence of what should record it.

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Eoarchean4.03 Ga → 3.6 Ga

The dawn era, and the first four hundred million years for which any rock survives at all. What it holds is thin, contested, and among the most important evidence there is.

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Paleoarchean3.6 Ga → 3.2 Ga

Four hundred million years in which life stops being a contested trace and becomes a structure you can walk up to and touch.

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Mesoarchean3.2 Ga → 2.8 Ga

Somewhere in this era the crust may start behaving as it does today, one plate sliding beneath another and driving the machinery that builds continents.

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Paleoproterozoic2.5 Ga → 1.6 Ga

Nine hundred million years, and the most violent change the planet has undergone: the air fills with oxygen, and almost everything alive is poisoned by it.

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Mesoproterozoic1.6 Ga → 1 Ga

Six hundred million years in which, as far as anyone can tell, remarkably little happens. They sit at the heart of what the literature calls the boring billion, and the nickname is a confession.

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Neoproterozoic1 Ga → 539 Ma

Four hundred and sixty million years in which ice reaches the tropics more than once, a supercontinent breaks apart, and the first animals appear.

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Paleozoic539 Ma → 252 Ma

Two hundred and eighty-seven million years, from the first shelled animals to the worst extinction in the record. Life leaves the water in this era and never fully returns.

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Mesozoic252 Ma → 66 Ma

A hundred and eighty-six million years between two catastrophes: the only era on the chart that both begins and ends with a mass extinction.

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Cenozoic66 Ma → 2026

The last sixty-six million years, in which mammals inherit a world emptied by an asteroid, grasslands spread, ice returns, and one primate lineage ends up drawing timelines.

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