Between 208 and 144 million years ago, dinosaurs inhabited the Earth's surface and became a dominant group in terra firme environments. Many of these animals were herbivores, but there were some carnivorous species that fed on amphibians, insects and even other dinosaurs.
At the end of the Cretaceous period, the extinction of dinosaurs and several other species of animals and plants occurred. There are many theories about this mass extinction of living organisms, and one of them is that certain movements suffered by the continents caused changes in sea currents and also in the climate of the planet. This caused the temperature to drop, which caused more severe winters, consequently leading to the disappearance of living beings that inhabited the Earth.
Another theory about the extinction of dinosaurs, and the one that is most accepted by the scientific community, is that an asteroid with approximately 10 km in diameter has reached the Earth's surface, generating an explosion similar to 100 trillion tons of TNT.
In 1990 this theory was reinforced after a group of scientists found a crater in Mexico approximately 180 km in diameter. Geological studies carried out at the site suggest that this collision would have occurred 65 million years ago, coinciding with the time of the extinction of the dinosaurs. Another very important factor that gives great support to this theory is the discovery of a large concentration of iridium (rare mineral on Earth, but often found in meteorites) in rocks of the period Cretaceous.
Many studies carried out suggest that the extinction of living organisms that inhabited the earth's surface it did not happen because of the impact of the asteroid with the Earth, but because of the effects that this impact caused. One of the consequences was the burning of large areas of forest, which destroyed habitats, exterminating the base of food chains, in addition to causing great air pollution.
Soot and dust from the asteroid's impact with Earth covered the entire sky, preventing sunlight from reaching the surface, leaving the Earth cold and dark. This caused photosynthetic plants to die, causing entire food chains to collapse, even in areas that were not hit by the fires.
Even with the disappearance of countless species, some life forms managed to survive. When they found an environment with adequate conditions, they began to proliferate, creating new habitats and consequently new ecological niches.
By Paula Louredo
Graduated in Biology
Source: Brazil School - https://brasilescola.uol.com.br/animais/a-extincao-dos-dinossauros.htm
