When the phrase "extinction of dinosaurs" is said, most of us have probably the idea of a giant asteroid hitting Earth, obscuring sunlight, cooling the planet, and the death of animal species due to lack of food. But is this idea correct? And did the dinosaurs really die out?
The mass extinction of animal species is nothing out of the ordinary on our planet. So far, about 20 mass extinctions are known in the history of the Earth, of which 5 are considered the so-called Big Five. The sixth mass extinction is then referred to in connection with the ongoing extinction in the anthropocene, i.e. in the era of the people. In addition to human activity, we can name increased volcanic activity, asteroid impact, climate change, sea level drop, or even a gamma flash. When we talk about dinosaurs, we mean the fifth great extinction, the so-called Cretaceous-Paleogene extinction, which happened about 66 million years ago.
The journey to the asteroid impact hypothesis and the discovery of a probable candidate took 11 years. In 1980, scientists examining a layer settled from the late Cretaceous period noticed that the rock contained a high concentration of iridium. An element that is very rare on the earth's surface, but on the contrary abundant in small extraterrestrial bodies. So, it was clear to scientists that they had to track down a sufficiently large crater, about 66 million years old. There were several candidates, but in the end the crater on the Mexican Yucatán Peninsula with a diameter of 180 km proved to be the most probable.
We know for sure that the impact caused a global megatsunami, that it affected climatic conditions, and that large dinosaurs lived for several thousand years after the event. The plausible scenario that the cooling of the planet and insufficient photosynthesis of plants caused a lack of food for herbivores and a lack of herbivores again caused a lack of food for carnivores seems to be generally accepted. However, it is uncertain whether the asteroid impact itself was the cause. Other findings point to strong volcanic activity in present-day India lasting about 800,000 years. However, studies in recent years have shown that volcanic activity has had a rather supportive effect and could have been partially accelerated by the impact of an asteroid. In addition, falling sea levels have been cited as a possible cause, which has also led to climate change.
Every great loss also means an opportunity for someone else. The resulting vacuum in the animal kingdom was eventually filled by an animal species that was until then a minority - mammals. When we talk about dinosaurs, we must also note that they did not die out 100 % either. Tiny theropoid dinosaurs developed the ability to fly more than 160 million years ago, surviving the fifth great extinction. Instead of dinosaurs, we prefer to call them birds today.