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How did the extinction at the Cretaceous-Paleogene boundary affect dinosaurs?

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Messinian Stage — Tertiary Period Gypsum cones, which resulted from the evaporation of the Mediterranean Sea during the Messinian Salinity Crisis, in the Sorbas basin, Spain.

At the Cretaceous-Paleogene (K-Pg) boundary, approximately 66 million years ago, a mass extinction event resulted in the extinction of all non-avian dinosaurs. While this event devastated many forms of life, it is important to note that dinosaurs did not leave the world entirely without descendants; birds (class Aves) evolved from small theropod dinosaurs and survived the extinction.123

The exact cause of this extinction remains a subject of scientific study, with the asteroid theory being a prominent explanation. This hypothesis suggests that a large asteroid impact triggered environmental catastrophes—such as global darkness, the cessation of photosynthesis, and extreme temperature fluctuations—that disrupted food chains and led to the collapse of many ecosystems. Other contributing factors may have included volcanic activity and long-term climatic changes resulting from plate tectonics. The disappearance of non-avian dinosaurs marked the end of the Mesozoic Era and facilitated the subsequent evolutionary expansion of mammals and other modern biota during the Cenozoic Era.24516