Rise of the Mammals

Dinosaurs-Jun-12-BlogWhen did mammals become abundant? Ask most people that and they’ll say 66 million years ago, after the dinosaurs became extinct. That’s what scientists have thought for a long time but, according to a study published last Wednesday, mammals were flourishing 20 million years earlier than that alongside the giant reptiles.

It has traditionally been thought that, because of the dominance of dinosaurs, the success of mammals was limited and they were no larger than rats. New fossil finds however have shown that mammals were quite a diverse group with some the size of modern dogs and others which had developed hooves.

Another thing that the study found was that, far from helping mammals, the extinction event which wiped out the dinosaurs also had a devastating effect on them. The few mammal species which did survive tended to be jacks-of-all-trades rather than specialists.

This is a common theme of evolution and one which we can see in action today. Animals and plants which depend on a specific habitat or on another species cannot adapt when that is taken away. Take a flower fertilised by a particular type of bee for example. If that bee is wiped out, perhaps through our use of pesticides, then the flower will no longer be pollinated and so will not reproduce – it will become extinct.

Mass extinctions have happened before but the one going on now is the first to be caused by a particular species. Our activities can have a catastrophic effect on the rest of nature. We may do as much harm to the Earth as that asteroid which wiped out the dinosaurs – unless something is done soon, it will be much worse. We have the power to completely destroy all life on Earth. We here at Education Quizzes certainly hope that we never use it!

There aren’t many dinosaurs around anymore, but their descendants are almost everywhere – birds. Take a look at our free to play Nature quizzes where you’ll find thirty devoted to these modern day dinos. You’ll also find quizzes on mammals, plants, trees, and just about every other branch of the evolutionary tree. Have a look and test your natural knowledge!

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