Dinosaur
Dinosaurs were a diverse group of reptiles that first appeared in the Triassic Period and dominated terrestrial ecosystems for much of the Mesozoic Era.
Dinosaurs were a diverse group of reptiles that dominated land ecosystems for over 230 million years. Non-avian dinosaurs went extinct 66 million years ago, but birds are their living descendants.
What it is
Dinosaurs belong to the clade Dinosauria and first appeared in the Triassic Period, flourishing through the Mesozoic Era. They spanned a huge range of sizes and diets, from small carnivores to massive herbivores. Scientific classification places them as reptiles, with birds considered avian dinosaurs.
Key details
Non-avian dinosaurs vanished at the end of the Cretaceous, about 66 million years ago. The leading cause is the Chicxulub asteroid impact, though volcanic eruptions and climate shifts may have added pressure. Scientists continue to discover new species; the total number of known types is not fixed.
Why it matters
Birds are the only surviving dinosaur lineage, making dinosaurs a living part of our world. Canadian researchers and museums have contributed key finds, especially in Alberta and western Canada, helping to piece together dinosaur evolution and extinction.
In short
- Dinosaurs lived for at least 230 million years, ending 66 million years ago.
- The Chicxulub asteroid impact is the main extinction cause.
- Birds are the living descendants of dinosaurs.
- Dinosaurs included many sizes and diets, with new species still being found.
Canadian scientists and museums have contributed to dinosaur research, including major fossil finds in Alberta and other parts of western Canada.
Quick questions
What killed the dinosaurs?
How long ago did dinosaurs live?
Are birds dinosaurs?
Sources
- National Geographic — https://www.nationalgeographic.com/science/article/dinosaur-extinctionSupports: Dinosaurs lived for at least 230 million years and non-avian dinosaurs ended about 66 million years ago.
- Natural History Museum — https://www.nhm.ac.uk/discover/how-an-asteroid-caused-extinction-of-dinosaurs.htmlSupports: Asteroid impact explanation, date of extinction, and note that the Alvarez hypothesis is the most widely accepted theory.
- Natural History Museum — https://www.nhm.ac.uk/discover/dinosaur-extinction.htmlSupports: Non-avian dinosaurs disappeared 66 million years ago; birds survived; asteroid impact and possible volcanic/climate contributions.
- Britannica — https://www.britannica.com/story/what-happened-to-the-dinosaursSupports: Asteroid impact narrative and approximate timing of dinosaur extinction.
- American Museum of Natural History — https://www.amnh.org/explore/news-blogs/dinosaur-extinction-eventsSupports: Birds as surviving dinosaurs and impact on ecosystems.
- University of Texas at Austin — https://news.utexas.edu/2021/02/24/asteroid-dust-found-in-crater-closes-case-of-dinosaur-extinction/Supports: Evidence linking asteroid dust in the crater to the extinction event.