Unfortunately, a number > of circumstances, like freaks of biology (the Natives got pummeled by > smallpox, instead of the Natives having the immunity to the disease and the > newcomers getting pummelled) has left not nearly as many Native Americans > with us in the present day.
Not so much a freak of nature as a consequence of history, Small pox jumped from heard animals to humans. There were more heard animals in Eurasia. Because Eurasia was more crowded it was a perfect envirnoment for small pox to spread. The disease had wrecked havoc on Eurasia for milenia (there is evidence for the disease in Egyptian mummies). So the population of europe had developed relative resistance (natural selection at work). The americans had no such long exposure. the disease wiped them out.
