What Happened To The Dinosaurs?
Part of Dinosaur Week
Dinosaurs lived on Earth for 180 million years – that’s a really long time! Modern humans have only been around for 200,000 years, that’s 1/900 as long as dinosaurs were around! If we try to visualise that, the UK is a little more than 900 km long. The existence of dinosaurs would take up the whole length of the UK, and modern humans would only take up 1 km – that’s a little less than half of the Tay Road Bridge!
We know that dinosaurs went extinct – or died out – at the end of the Cretaceous Period rather abruptly. So how did these gigantic animals suddenly disappear?
Scientists are still trying to work that one out. There are lots of theories that might point to why the dinosaurs went extinct during this time. One well-known theory is that an asteroid or comet hit the Earth in what is today the Yucatán Peninsula off the coast of Mexico. The meteor is believed to have been about 10 and 15 km wide. When it hit the Earth, the asteroid itself vaporised, but it sent tidal waves and a shockwave and heatwave out. It threw up so much soot and debris that it reduced the amount of sunlight that could reach plants. The area right around the impact was completely destroyed. Because plant life began to die, herbivores did not have enough food, which meant eventually, carnivores would have less food as well. These very large animals could not find the food they need to sustain their body masses, and so they would have died as well. About 75% of the animals on Earth would have died after this event.
However, the asteroid wasn’t the only baddie here. During the Cretaceous Period, there was a lot of fluctuation in sea levels and climate change. The Earth was undergoing another climate change when all of this happened. Because the continents were splitting, there was a lot of volcanic activity going on, which also increased the temperature, and made it harder for life to exist in certain areas.
After the asteroid impact, flowering plants dominated the Earth, and large animals over 25 kg died out. The only dinosaurs that survived were birds. If you’ve ever eaten chicken nuggets… you’ve eaten dinosaur nuggets! Small mammals, birds, and other animals survived and life similar to today began to flourish.
So, what would have happened if the asteroid had not hit or had hit somewhere else? We’ll probably never know, but the world today would definitely have looked a little different!
This page is part of the Dinosaur Week information.
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