The dinosaurs are extinct
Dinosaurs lived on Earth for more than 65 million years. If we summarized the Earth's history over a year, Dinosaurs would have ruled for two weeks, compared to humans, who would have been here for only two hours.
In the collective imagination, all the dinosaurs suddenly died out at their peak following an unprecedented cataclysm, which makes 3 received ideas.
Indeed, there have regularly been mass extinctions throughout the history of life, and the Cretaceous/Palogenian one is no more important than the others. It would have taken away 50% of living species, whereas the Permian/Triassic extinction, for example, ravaged 95% of all living things on Earth.
Extinctions are often imagined as something immediate, but extinctions are not sudden episodes but long periods of crisis that can last for thousands of years.
Each of the extinctions has been caused by changes at the planet's scale. A rise or fall in temperature, a change in the composition of the air or a change in the acidity of the oceans, for example.
If a change affects the entire globe and is too fast for animals to adapt, most of them will die. The extinction of the dinosaurs is dated at 65 million years ago. In Chicxulub, Mexico, a crater has been found caused by a 10 km diameter meteorite, which is believed to have hit the Earth 65 million years ago. Traces of very strong volcanic activity have also been found in the Deccan Traps in India during the same period, which must have played a role as well.
But volcanic eruptions and this meteorite did not directly wipe out the dinosaurs. These permanent eruptions and the phenomenal amount of dust raised by the fall of this meteorite have caused an upheaval in the atmosphere. And like the previous extinctions, it's probably this upheaval that killed the dinosaurs bit by bit.
The opaque atmosphere would have limited solar radiation and photosynthesis, preventing plants from developing properly. Deprived of food, large herbivores would have died, then their predators. Only small animals, insectivores and scavengers would have survived.
But recent studies seem to indicate that several million years before these phenomena, dinosaurs were already in decline. Especially the large specimens, whose numbers were falling significantly, and whose diversity was declining over thousands of years, signalling a predicted extinction.
Some scientists, therefore, believe that the Chicxulub meteorite and the eruptions of the Deccan Trap were only a death blow to a group of decadent animals whose reign was nearing its end.
Finally, not all the Dinosaurs Disappeared, one of the most famous species survived: the theropods. Representatives of this family are still with us, the birds.
When we compare the skeletons of the theropods of that time with those of today's birds, we note they are almost similar.
In conclusion, even if a large part of the dinosaurs disappeared, some species survived and we find today some of their descendants.
