If set Ethereum next to Bitcoin, it is easy to see that both are good candidates to call for investment in the ICO and all operate on the Blockchain protocol. However, every electronic money is born to build a strategy for their own, to make a difference.
As for the origin, simply understand that Bitcoin was created and valued as a currency to hold values, while Ethereum was more inclined to create a platform based on smart contracts. Supply is also another difference of these two currencies. Bitcoin is only 21 million, so far has circulated in the market about ? the amount it has, and Ethereum there are no limits, but have to wait until this 5-year old coins to exploit only ½ The possibility of being hacked by Ethereum is higher than the rest of the currency because Ethereum runs Turing-complete code, if enough time then all the calculations will be done.