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Why do eyes have pupils? Evolution and Biology

By |2017-05-27T15:32:08+00:00May 27th, 2017|Biology|

By around 550 million years ago, some kinds of worms evolved eyespots sunk into their heads to protect them from being damaged. As a side effect, it turned out that being sunk into the head also helped to focus the light on just one spot, so that more light reached that spot and the worm could see [...]