Originally Posted by sjohnston
i know this is remotely random...but in one of my classes we learned that the way humans are built has a lot to do with the climate that they were struggling to survive in...i.e. humans that had to live in a very cold climate were stockier and shorter where as humans that lived in places that were very hot were leaner and taller...a lot of evolution in our bodies had to do with retaining heat and the ability to cool ourselves off.
Adapting to physical environments is the #1 factor in evolution:
Just like why Giraffes have long necks; it's because the ones with shorter necks all died out over a long period of time. They died out because they could not reach the tops of the trees to eat the leaves.
That is how we have giraffes.