> But every trait or behaviour that survives on evolutionary timescales does serve (or did serve, in the case of vestigial features) a purpose. This is in fact

> But every trait or behaviour that survives on evolutionary timescales does serve (or did serve, in the case of vestigial features) a purpose. This is in fact not true. There are "coincidences" of evolutionary biology and if there is not selective pressure to change them, they remain for millions of years.