Timeline of Life

By | September 9, 2016

Earth’s history stretches back 4.6 billion years to our planet’s birth. Scientists divide this vast span of time into different periods, such as the Jurassic Period, when many of the dinosaurs lived. Here you can see all the periods on a timeline showing the history of life.

THE LINES TELL TALES

The past leaves clues buried in the rock below our feet. Certain types of rock build up in layers (strata) over millions of years. Different layers correspond to different periods in Earth’s history.

GRAND CANYON

grand-canyon-arizona-usa

The Grand Canyon – Arizona, U.S.A.

The different periods in Earth’s history are named after the layers of rock in which fossils are found. At the Grand Canyon, you can see these ancient rock layers, which get older toward the bottom.

EARTH’S HISTORY

It’s divided into very long stretches of time called eras. These are further divided into shorter stretches called periods, such as the Jurassic and Triassic:

ERAS AND PERIODS


Paleozoic Era


CAMBRIAN: 542–488 million years ago

cambrian

Trilobites scuttled around on the seafloor

ORDOVICIAN: 488–444 million years ago

ordovician

Starfish (sea stars) became common in the sea

SILURIAN: 444–416 million years ago

silurian

Pseudocrinites anchored itself to the seabed in the late Silurian.

DEVONIAN: 416–358 million years ago

devonian

Dunkleosteus, a giant predator, terrorized the seas

CARBONIFEROUS: 358–299 million years ago

carboniferous

Dragonflies and other insects buzzed through the air

PERMIAN: 299–251 million years ago

permian

Dimetrodon was the most fearsome predator of its time

 


Mesozoic Era


TRIASSIC: 251–200 million years ago

triassic

The first dinosaurs appeared, one of the earliest known being Herrerasaurus.

JURASSIC: 200–145 million years ago

jurassic

The earlies known bird, Archaeopteryx, appeared

CRETACEOUS: 145–65 million years ago

cretaceous

The first mammals were small, mouselike animals

 


Cenozoic Era


PALEOGENE: 65–23 million years ago

paleogene

One of the earliest known primates, Eosimias, appeared in this period

NEOGENE: 23 million years ago

neogene

Our apelike ancestors began walking

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