The Age of Reptiles in Three Acts
PBS Eons・12 minutes read
The Mesozoic Era saw the rise of archosaurs and dinosaurs, evolving and adapting to changing environments over millions of years. The extinction event at the end of the era wiped out giant reptiles, paving the way for the dominance of mammals and smaller creatures in the Cenozoic era.
Insights
- The Mesozoic Era, starting after The Great Dying, saw the emergence of archosaurs like dinosaurs, pterosaurs, and phytosaurs in the Triassic Period, with unique adaptations such as pubis bone orientations distinguishing different dinosaur groups.
- The K-Pg Extinction event 66 million years ago marked the end of the Age of Reptiles, leading to the demise of giant reptiles like dinosaurs and the rise of mammals due to their smaller size and varied diets, ultimately shaping the dominance of smaller species in the Cenozoic era.
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Recent questions
What era followed The Great Dying?
Mesozoic Era
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Summary
00:00
Evolution and Extinction of Dinosaurs
- A quarter of a billion years ago, the Mesozoic Era began after The Great Dying, wiping out most species and leaving a world open for survivors.
- In the Triassic Period, archosaurs, including dinosaurs, pterosaurs, and phytosaurs, emerged and adapted well to the changing environment.
- The first dinosaurs, like Nyasasaurus, Eoraptor, and Herrerasaurus, appeared in the Triassic, with saurischians having a unique pubis bone orientation.
- By the Jurassic Period, ornithischian dinosaurs evolved with a reversed pubis bone, allowing for larger gut cavities to digest tough plants.
- Mammals diversified in the Jurassic, with species like Megazostrodon coexisting with dinosaurs.
- The Cretaceous Period saw the rise of flowering plants and the evolution of large, feathered theropods and titanosaurs.
- Pterosaurs grew larger, with azhdarchids becoming the largest flying animals, while tyrannosaurids dominated as apex predators.
- The Late Cretaceous marked the peak of dinosaur diversity, with groups like hadrosaurs, ceratopsians, and ankylosaurids flourishing.
- The K-Pg Extinction event 66 million years ago, caused by massive volcanic eruptions and an asteroid impact, led to the demise of giant reptiles, including dinosaurs.
- The extinction marked the end of the Age of Reptiles, wiping out most large reptile species and paving the way for the rise of mammals and other smaller creatures.
10:02
Survival and Evolution in Mesozoic Era
- 75% of the world's species disappeared during the Mesozoic era, but some survived due to their small size and varied diets, including the three modern mammal groups: placentals, marsupials, and monotremes. Flowers that bloomed in the Cretaceous era are now more abundant, and some archosaurs like crocodilians and birds have persisted, with birds being the last surviving saurischian theropod dinosaurs. The giant reptiles of the Mesozoic era faced downfall due to their large size and specialization, while smaller species thrived, leading to their dominance in the Cenozoic era.
