I just read this article on the evolutionary divergence between humans and chimps, and how the most significant event was when the 24 number of chromosomes in chimps was reduced to 23 in humans due to chromosomal fusion. However, while this even significantly supports the theory of evolution, how does this affect natural selection? What phenotypical changes may have occured between these two groups because of the chromosomal fusion? And what if chromosomal fusion did not occur? Would speciation still occur by other means, e.g. geographic isolation?