Evolution and plants/trees: How do plants know how to shape their seeds?

Evolutionarily speaking: how did/do trees know how to shape their seed 'carriers'? (i.e. the helicopter seed or whirlybirds)...and how did the dandelion know how to make the fuzzy white things that carry their seeds? And how would they determine if it was a 'success' or not? Do trees have intellect to figure how to "package" their seeds in the most efficient manner, or perception of distance, or measures of 'success'?