Short answers, pulled from the story.
The Cretaceous Paleogene extinction event occurred approximately 66 million years ago and caused the extinction of all non-avian dinosaurs. This event marked the end of the Mesozoic Era and allowed surviving avian dinosaurs to diversify rapidly during the Paleogene period.
Sir Richard Owen coined the term dinosaur in 1842 to describe great fossil lizards as a distinct taxonomic group. The word means terrible lizard and was established to categorize these ancient reptiles following earlier discoveries by William Buckland and Gideon Mantell.
Dinosauria is defined as the group consisting of the most recent common ancestor of Triceratops and modern birds and all its descendants. This definition includes both extinct non-avian dinosaurs and the avian dinosaurs that survived the extinction event approximately 66 million years ago.
There are over 11,000 living species of birds walking flying and swimming across the globe today. Birds are dinosaurs and represent the sole surviving lineage of a group that once dominated terrestrial vertebrate life for over 180 million years.
The renaissance in paleontology began in the 1970s and overturned a century of misconceptions about dinosaurs being sluggish cold-blooded lizards. This shift established that dinosaurs were active animals with elevated metabolisms complex social behaviors and avian respiratory systems.
Evidence from trackways and fossil sites shows that many species traveled in great herds and engaged in pack hunting. The discovery of a nesting ground for Maiasaura in Montana in 1978 provided the first concrete evidence that dinosaurs cared for their young.