Timeline

The more or less accepted timeline of living things on earth goes as follows: Single cell organisms appeared on earth about three and a half billion years ago. About 500 million years ago, simple plants and animals appeared followed by more complex plants and animals. While there is some argument about the order and when things appeared, it seems that the fossil record supports the idea that different species appeared at different times and the progression went from simple to more complex. If the universe was created, why would the creator do this? Why not just create the complete ecosystem as it stands today? What would be the point in waiting all those years? It also seems curious that a creator would create from simple to complex. There are those that believe that there is a creator that used evolution to advance life on earth. This would answer a number of the problems in both theories but still, why would the creator go from simple to more complex life at different times? It almost seems like the creator needed the practice but why would a being powerful and creative enough to make the universe need practice? As usual, I have more questions than answers.