system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why did birds evolve with wings if they did not instantly work?

before wings allowed creatures to fly, were they just oddly shaped legs that didn't work as well? how did these help these creatures survive and pass on their genes?
gpt
There is two theories

1) ground up, where the reptiles with feathers would flap their arms to generate just enough lift to catch flying insects, therefor survived better and passed on genes. 

2) tree down, where the reptiles would use there wings to glide along with there mouth open and catch flying insects, therefor increasing survival and passing on genes. 

at this point in time no animal was real tapping into the food source that was flying insects. all animals were land/sea roaming, so these species were excelling and passing on genes. over time they evolved to get better and better at flight and evolved to the point of birds with continuos flight.