The Evolution of Life
4567 Ma – ongoing47 items
deep timeevolutionFour billion years, from one cell to all of us
From the last common ancestor of everything alive to the species reading this. For nearly three billion years life was microbes alone. Then came oxygen, complex cells, two Snowball Earths, the first animals, the Cambrian explosion, the move onto land, forests, flowers, grass, the mammals, and at the very end, us.
How to read it
The four eons — Hadean, Archean, Proterozoic and Phanerozoic — run along the top, and the Phanerozoic’s three eras below them. Zoom out and the eras shrink to a sliver: animals fill only the last eighth of the story.
Story periods — the Great Oxidation Event, the “boring billion”, two Snowball Earths, the Ediacaran biota, the Cambrian explosion — overlap them.
Every fossil is pinned where it was found, from the Pilbara and Greenland to Gabon, Yunnan, the Rockies, Liaoning and the Fayum.
Threads to follow
microbes— the first three billion yearsoceans— from Ediacaran fronds to whalesland— spores, forests, fish with wrists, eggsplants— algae to flowers and grasslandmammals— from sail-backed Dimetrodon to usextinction— the Big Five, and a possible sixthcontroversy— the oldest claims for life, and why each one is disputed
The dinosaurs get only a glimpse here; The Age of Dinosaurs tells their 186 million years in full, and Human Origins picks up the last seven million where this timeline hands over.
There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved. — Charles Darwin, On the Origin of Species, 1859
Dates are years before present, with the uncertainty their sources give. Eon, era and period boundaries follow the International Chronostratigraphic Chart.
Items
LUCA, the last universal common ancestor
Carbon in a Jack Hills zircon
Isua stromatolites?
Strelley Pool stromatolite reef
Francevillian biota
Complex cells in the fossil record
Bangiomorpha, the oldest known sex
Dickinsonia at Ediacara Hills
The Cambrian begins at Fortune Head
Chengjiang biota
Burgess Shale
First land plants
End-Ordovician extinction
The oldest complete jawed fish
Rhynie chert
Footprints at Zachełmie
The oldest forest
Tiktaalik
Late Devonian extinction
Hylonomus, the first egg-layer on land
Meganeura, the giant griffinfly
Dimetrodon
The Great Dying
First dinosaurs
End-Triassic extinction
Archaefructus, an early flower
Grass in dinosaur dung
Chicxulub impact
Purgatorius, the first primates’ kin
Whales with feet at Wadi Al-Hitan
Proconsul on Rusinga Island
Homo sapiens
A sixth mass extinction?