We evolved from hominids that had longer jaws for chewing raw meat and plants. Extra molars are an advantage, but they don’t emerge until adulthood. This gives the jaw time to grow large enough to accommodate them. As teeth are widest at the top, spaces between them can also emerge as the molars start to wear down. The new teeth at the back encourage the remaining teeth to shu#e up and close the gaps. We don’t need wisdom teeth any more, nor do we have enough room for them. But dentistry o"ers a quicker fix than evolution.