Comment by mirimir

That's pretty much how our brains develop. Neurons are vastly overproduced, during fetal development through the first few years. Ones that make useful connections, and do useful stuff, survive. And the rest die.

Also, as in evolution, ~random variations occur during neuronal proliferation, so there's also selection on epigenetic differences. The same sort of process occurs in the immune system.

In this way, organisms can transcend limitations of their genetic sequences. There's learning at levels of both structure and function.