cool topic well as u may know of may not, our height is contolled mainly by the percentage of oxygen we get as if u have recently watched walking with monster:before the dinosaurs there was a certain era in which the was alot of oxygen and therefore a normal dragon fly was the size of a cow and a spider was as big as your face! sorry to go off topic a bit um im not sure wat we will evolve into but after 50 we will certainly be growing stronger as then all of the fossil fuels will run out