An evolutionary branch · still aliveOur World

Dinosaurs to Birds

Explore the fossils connecting birds with theropod dinosaurs, from early dinosaurs to living feathered descendants.

Subject guide · scope, chapters & sources ↗

Origin depth

Official Earth time scaleSelect an eon on the road to reveal its eras.ICS 2026/06 ↗

Cosmic Originsbefore Earth’s geological eons

c. 13.8 billion years agoUniverse

The Big Bang

The universe expands and cools from a hot, dense early state.

Oval map of small temperature differences in the cosmic microwave background. — ESA and the Planck Collaboration / NOIRLab · CC BY 4.0

Within the first few hundred million yearsEarly Universe

The first stars ignite

Gravity gathers primordial gas and the cosmic dark ages begin to lift.

Illustrated cosmic timeline marking the dark ages, first stars and galaxies. — NASA, ESA, CSA, STScI · NASA editorial media-use permission

c. 4.54 billion years agoSolar System

Earth takes shape

Rock and metal gather around the young Sun.

Dark, crusted Allende meteorite fragment. — Jon Taylor · CC BY-SA 2.0

At least 3.5 billion years agoEarth

Microbial life leaves evidence

Ancient rocks preserve traces of a living planet.

Layered Paleoarchean stromatolite specimen. — Didier Descouens · CC BY-SA 4.0

c. 2.4 billion years agoAtmosphere & oceans

Oxygen transforms the atmosphere

Microbial photosynthesis changes the chemistry of Earth.

Blue-grey banded iron-formation specimen on a museum stand. — Kjoonlee · CC BY 4.0

c. 1.8 billion years agoEarth

Complex cells diversify

Cells with internal structures establish a new branch of life.

Light-microscope view of modern Paramecium caudatum cells. — Fritzmann2002 · CC BY-SA 4.0

c. 600 million years agoGlobal oceans

Large multicellular life spreads

Complex bodies become a visible part of the fossil record.

Oval, segmented Dickinsonia fossil impression in rock. — cprevot (https://www.geodiversite.net/auteur193) · CC BY-SA 3.0

c. 230 million years agoSouth America

Dinosaurs enter the fossil record

Late Triassic fossils document an early dinosaur world.

Mounted Herrerasaurus skeleton in a museum gallery. — Zissoudisctrucker · CC BY-SA 4.0

c. 165–150 million years agoAsia

Feathers before modern birds

Some non-avian dinosaurs already wear feathered coverings.

Flattened Anchiornis skeleton and feather impressions on a stone slab. — ★Kumiko★ from Tokyo, Japan · CC BY-SA 2.0

c. 150 million years agoEurope

Archaeopteryx combines old and new

Feathered wings occur alongside teeth and a long bony tail.

Archaeopteryx fossil with spread wings and a long tail in a limestone slab. — H. Raab (User: Vesta) · CC BY-SA 3.0

c. 125 million years agoEurope

Early birds take to diverse skies

A fossil wing preserves evidence of sophisticated feather control.

Palaeontological fieldwork at the layered rock exposures of Las Hoyas. — PePeEfe · CC BY-SA 4.0

c. 66.7 million years agoEurope

A fossil near the modern bird family

Asteriornis lives shortly before the end-Cretaceous extinction.

Four rock matrix blocks preserving parts of the Asteriornis holotype. — Daniel J. Field, Juan Benito, Sarah Werning, Albert Chen, Pei-Chen Kuo, Abi Crane, Klara E. Widrig, Daniel T. Ksepka, and John W.M. Jagt · CC BY 4.0

c. 66 million years agoGlobal

An extinction reshapes the living world

Non-avian dinosaurs disappear, but some bird lineages survive.

Grey boundary layer between reddish and yellowish tilted rock beds at Zumaia. — M. Schaap · CC BY-SA 4.0

Present dayGlobal

The dinosaurs outside your window

Every living bird belongs to the dinosaur family tree.

Male house sparrow perched with its head turned to the side. — Jolanta Dyr · CC BY-SA 3.0 pl

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