Wednesday, August 17, 2011

Reassembling Pangaea In The Year 1493

This is the second great talk I have heard on Fresh Air in the past few days. Author of the book 1493: Uncovering the World Columbus Created Charles Mann talks about the impact on the Americas and Europe due to the sudden exchange of humans, animals, plants, parasites between the continents following Christopher Columbus's voyage to the America's in 1492.

He frames this exchange within a larger geological context -

Mr. CHARLES MANN (Author, "1493: Uncovering the New World Columbus Created"): Well, if you think about it, you know, there's been a tendency in textbooks now to kind of downplay Columbus because they say he was a bad guy, and he mistreated Indians, and he discovered the Americas by accident and so forth.

But to ecologists, he was this super-important figure, and the reason is that 200 million years ago, as you remember learning in school, the world was a single, giant land mass they call Pangaea, and geological forces broke it up, creating the continents we know today. And over time, they developed completely different suites of plants and animals.

And what Columbus did was bring the continents back together. He recreated Pangaea, in effect, and as a result, huge numbers and plants and animals from over there came over here, and huge numbers of plants and animals from over here came over there, and there was a tremendous ecological convulsion, the greatest event in the history of life since the death of the dinosaurs.

As an aside.. he is right off course that after the supercontinent Pangaea broke up more than 200 million years ago, different continents had evolved different suites of plants and animals. But Europe, Asia and the America's were not completely isolated from each other from the breakup of Pangaea until the Columbian exchange. From time to time during the early Cenozoic there were faunal exchanges ..mammals especially migrating via the Beringia land bridge (Siberia -Alsaka) to and from between Asia and America and via the Greenland land bridge in the early Cenozoic between Europe and America. These immigrants also must have caused ecological upheavals of their own. They would have been competition for resources and they must have brought over parasites and caused much death and destruction. We have a more guilt free dispassionate view of these faunal turnovers and extinctions. Tim Flannery has the details of these ancient exchanges that took place tens of millions of years ago and the ecological history of the America's in his excellent book The Eternal Frontier.

Charles Mann though weaves many fascinating stories of the Columbian exchange. One that caught my eye was on the impact of malaria on the institution of slavery. The climate which made the southern parts of the America's friendlier to intense plantation agriculture were also environs in which malaria thrived. Africans were more resistant to this newly introduced disease while indentured servants from Britain and Europe who were more commonly hired to work the fields in the earliest days of colonial settlement were dying off in great numbers. It made economic sense to start bringing over more Africans to work on the plantations.

The word exchange means that the movement of people, animals, plants and diseases went both ways. The damage in terms of human deaths, deprivation and societal disruption though was overwhelmingly more in the America's. I have often come across a common impression that it was technology, firepower and political and financial institutions that gave Europeans the decisive advantage over Native Americans. Those did play a role, but the factor that titled events in favor of Europeans was the evolutionary history of peoples, rather resistance or lack thereof to disease. In a strange twist of fate, Europeans benefited from both a lack of resistance to certain diseases as well as from resistance to others. A lack of resistance to malaria stopped newly arriving European poorer classes from being tied to harsh servitude in plantations in the south where malaria was prevalent. Instead resistance to malaria lead Africans into bondage. On the other hand Europeans had evolved immunity against small pox and many infectious diseases contracted from domesticated animals from time to time. Native Americans had not encountered small pox before and not having a history of animal domestication lacked immunity against animal diseases that occasional jumped hosts. They died in their millions leaving vast swathes of countryside unattended and empty for European settlers.

America though had its grotesque revenge via the potato and guano which was used as a fertilizer. Originating in Peru, the two teamed up and initiated intense potato cultivation all across Europe. Ireland especially became addicted to the potato. But the spud carried with it a fungal parasite. In the mid 1800's the potato crop all over Europe failed. More that a million Irish died of starvation partly due to the blight and partly due to Britain's refusal to divert grain to Ireland.

One last fascinating demographic titbit about the role of Africans in building North America:

..And the second thing is that what happened after the Europeans came was not so much that Europeans came, but the Africans came. The number of Africans who came to the Americas up till about 1840, 1850 far outweighed the number of Europeans. There were three Africans for every European who came to the Americas in those first couple hundred years.

GROSS: And this is because of slavery.

Mr. MANN: Because of slavery. And so the Europeans who came, like, you know, many of my ancestors in the later part of the 19th century came to landscapes that had been radically changed, but they had - and to new cities. But those cities had been built (by) African hands, the landscapes had been reworked by African hands, the boats that were going up and down the rivers were piloted by African crews. And so that - there was a tremendous change in the very distribution of the human race on the planet as a result of Columbus.

Globalization has done great things to us as a people, but it has been served up with more than its fair share of pain.

1 comment:

  1. Suvrat, this is not really something new. Distance is not a barrier for colonisation by species over time.

    A small fact which I had the privilege to add to Wikipedia confirms this :