Mutual Funds and Exchange Traded Funds [ETFs] have many similarities, however Exchange Traded Funds were developed more recently to offer modern advantages and flexibility, especially to active investors.
The first successfully released ETF was the "SPDR" (S&P 500 Depository Receipt, commonly referred to as the "spider") in 1993. Mutual Funds have much more history dating back to the 1920's, before the Great Depression.