The evolution of dinosaurs covers their transformation from modest, bipedal reptilian ancestors into the dominant terrestrial vertebrates of the Mesozoic era, a reign lasting roughly 180 million years. Emerging in the late Triassic (about 230 million years ago), dinosaurs are members of the group Archosauria, which also includes modern birds and crocodilians. Their success was driven by a series of innovations—upright posture, efficient locomotion, diverse diets, and complex reproductive strategies—that enabled them to exploit new ecological niches. Through several adaptive radiations, dinosaurs diversified into myriad forms, from swift predators to massive herbivores, shaping ecosystems until their abrupt decline at the end of the Cretaceous.
- Originated as small, agile archosaurs in the late Triassic.
- Developed upright posture for efficient movement and energy use.
- Underwent major adaptive radiations, filling many ecological niches.
- Dominated terrestrial ecosystems for most of the Mesozoic era.
- Include the ancestors of modern birds, which survived the dinosaur extinction.
Dinosaurs first appeared in the Late Triassic period.
Dinosaurs belong to the Archosauria, the 'ruling reptiles.'
Upright posture, efficient locomotion, and diverse diets aided dinosaur success.
The Mesozoic Era is called the 'Age of Dinosaurs.'