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The 5th extinction and the rise of the mammals

Watch: Cretaceous extinction event and the rise of the mammals

With the fifth and last mass extinction at the end of the Cretaceous, 75% of all species were wiped out including non-avian dinosaurs, pterosaurs, and many early birds. In the marine environment, there were also large scale extinction of species such as the ammonites and large marine reptiles, as well as smaller invertebrates.

There is still much research being done into the details of this extinction event – including whether it was short-lived or lasted over a few thousand years. There are several likely causes the details of which are hotly debated among scientists. Nevertheless, there is some consensus that the main culprits were: asteroid impacts, volcanism and sea level changes. In my opinion, also shared by many other, it is more than likely that the End Cretaceous extinction event was probably the result of a combination of these causes.

Whatever the details of the cause, it was another great rolling of the dice that ended the domination of some species and opened up ecological niches for new species. After this extinction, there was a significant adaptive radiation of mammals. Earlier, I talked about the small early mammals that co-existed with dinosaurs – it turns out that although mammals also experienced some extinctions some of them survived the End Cretaceous extinction event – and from these surviving taxa, over 130 new genera comprising 4 000 different species radiated afterwards during the Palaeogene.

Next, I talk with three researchers to discuss their perspectives on different aspects of the development of life over the more recent past. They are William Bond, who is a terrestrial ecologist, Pippa Haarhoff, who is a palaentologist and Becky Ackermann, who is an archaeologist.

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Extinctions: Past and Present

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