Knowra Devonian Devonian The Devonian is a geologic period from about 419.2 to 358.9 million years ago. Its marine ecosystems diversified dramatically, and vertebrates began expanding onto land.
Geologic time scale : A chronology dividing Earth’s history into eons, eras, periods, and smaller units. The Devonian is one period within this larger chronology.
Devonian fish : Fishes that lived during the Devonian, when jawed and armored forms diversified extensively. Their radiation gives the period its familiar name, the Age of Fishes.
Tiktaalik : A 375-million-year-old fossil fish with features associated with early tetrapods, discovered in Arctic Canada. Its anatomy illustrates adaptations near the fish–tetrapod transition.
Evolution of tetrapods : The evolutionary history of vertebrates with four limbs and their descendants. The first tetrapods emerged from Devonian vertebrate lineages.
Paleozoic : The geologic era spanning roughly 539 to 252 million years ago, before the Mesozoic. The Devonian occupies the middle of this era.
Tetrapod : A vertebrate with four limbs or descended from four-limbed ancestors. Devonian tetrapods document vertebrate transitions toward life on land.
Acanthostega : An early tetrapod from the Late Devonian with limbs bearing digits and adaptations for aquatic life. It shows that digit-bearing limbs evolved before fully terrestrial locomotion.
Evolution of plants : The diversification and transformation of plant lineages through geological time. Devonian vascular plants and forests changed the structure of land ecosystems.
Silurian : The geologic period immediately preceding the Devonian, lasting about 443.8 to 419.2 million years ago. Its environments and early land ecosystems set the stage for Devonian changes.
Devonian reef : A reef ecosystem built mainly by stromatoporoids, corals, and other marine organisms during the Devonian. Extensive reefs supported diverse marine communities before the late-period collapse.
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