The evolution and diversification of life are nicely depicted by a tree – with the original first living organism at the root and the main branches splitting into still smaller branches and twigs that eventually lead to the living species at the leaves. But what about all the species that went extinct, you may ask. The dinosaurs found themselves in dire straits 65 million years ago. In fact, species go extinct all the time. Whereas recently emerged species most likely persist, species that arose hundreds of million years ago have most likely gone extinct since then. This continuously removes twigs and branches from the tree of life, which is why it has ended up looking like, well, a tree.
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