I believe that the East-West alignment of Eurasia is what lead to the European conquest of the Americas. Sure it was the diseases that arose from animal domestication that thinned the ranks of the Native Americans, but had it not been for the East-West alignment of Eurasia the Spanish never would have received the animals or crops that they did from the Fertile Crescent. Had that been the case they never would have developed the diseases which aided in their campaign against the Native Americas.
If the Americas had an East-West alignment and Eurasia didn’t then history would be very different indeed. Of course the Americas wouldn’t be the spitting image of what was Europe at the time of the Spanish conquest, but it would be much more advanced. Let us consider what was present in the Americas when the Spanish arrived. In Mesoamerica they domesticated corn, invented a wheel, developed a writing system and an empire. In the Andes they domesticated the llama and had widespread metal tools (as well as an Empire) (362). These were only a number of things these two Empires managed to accomplish, and I’m not including the Indians of the Eastern U.S. either. But imagine what could have happened if these isolated ideas and objects had the chance to spread. Perhaps plants domesticated in one area could be widespread throughout the Americas. The llama could travel and even be used for plowing, increasing the efficiency of agriculture. This increase in agriculture could lead to more sedentary societies in turn leading to more specialists which meant better technology. Perhaps the wheel developed by the Aztecs could be put to use as more than just a mere child’s toy. The writing system would spread and possibly even, through blueprint borrowing and idea diffusion, give rise to new languages spoken by more than just temple scribes. The metal tools could have developed into metal weapons. The once isolated areas would soon become enemy states which would lead to competition, in technology, between them. As Diamond says “technology begets more technology” the technology that would now be spreading throughout the Americas would constantly be improved by the autocatalytic process.
Now what would Spain, and the rest of Eurasia, have looked like if it were on a North-South alignment. Yes perhaps there would have been plant domestication, animal domestication, and even writing systems but all of these things would be in isolation from each other. Plants and animals that could live in one latitude cannot live in another. Due to the inability of language to spread it would likely remain a language used only for the scribes. So Eurasia would look a bit like the Americas did different technologies arising here and there, but in isolation and with little chance of spreading which also means with little chance of growing.