A recent study by 2 Japanese scientists has found that the dinosaur extinction was a very unlucky event (https://www.theguardian.com/science/2017/nov/09/unlucky-dinosaurs-no-extinction-if-asteroid-had-hit-almost-any-other-part-of-earth). The 9 km-wide asteroid thumped into what is now the Yucatan peninsula of Mexico and, at that time, it was part of only 13% of the Earth's surface where there were enough hydrocarbon reserves to generate a dust cloud sufficient to produce the world-wide climate change (with a chronic cutting off of sunlight and a 10 degree Celsius reduction in average temperature). This led to more than 3/4 of animals on land and in the sea being driven to extinction. Of course, what was bad news for the dinosaurs was very good news for the Mammals (whose retinal structures were rod dominated, suggesting that, whilst dinosaurs were around, had been limited to a nocturnal life-style). And so, we have the age of the Mammals. It is interesting to speculate that, if the asteroid had hit almost anywhere else, we would not now be potentially facing a mass extinction event largely driven by human activities (the so-called Anthropocene).
No comments:
Post a Comment