A Good or Bad Exchange?

In a recent video, The Columbian Exchange: Crash Course World History #23, by the amazing YouTube channel Crash Course (which I have promoted in the past on The Advanced Apes website – here – go now!), John Green finishes the video by basically asking the viewer to consider whether the Columbian exchange was good or bad.  He first acknowledges that the historian Alfred Crosby, who wrote the famous book The Columbian Exchange believed that it was one of the worst thing to happen in the history of humanity:

“Columbian exchange has included man, and he has changed the old and new worlds sometimes inadvertently, sometimes intentionally, often brutally.  It is possible that he and the plants and animals that he brings with him have caused the extinction of more species of life forms in the last four hundred years than the usual processes of evolution might kill off in a million.  The columbian exchange has left us with not a richer but a more impoverished genetic pool.  We, all of the life on the planet, are the less for Columbus, and the impoverishment with increase.”

John Green then leaves us with these important questions:

Do you agree with Crosby?  Are longer and healthier lives for more humans worth the sacrifice of an impoverished biosphere?  And most importantly how will your conclusions about those questions shape the way that live your life?

Alfred Crosby obviously makes some extremely thought provoking and valid points.  And John Green asks some incredibly difficult questions.  Can my seemingly endless optimism for humanity’s long term development (see: herehere and here) counter these points?  I’ll certainly try my best.

I do not agree with Crosby

Alfred Crosby is correct in asserting that our species has single handedly altered the biosphere in a way that may rightfully be compared to the five previous mass extinction epochs in the natural history of our planet.  However, he is wrong to conclude that that is A) an inherently bad thing and B) something that we cannot learn from and change in the future.

I am not arguing that impoverishing the genetic pool is bad (in fact I actively work to preserve genetic diversity in our closest relatives), but the fact is that massive global genetic bottlenecks have been a part of life history from the dawn of multicellular organisms, and life ALWAYS rebounds and diversifies in even more spectacular forms than before.  Take the example of the Triassic-Jurassic (T-J) extinction event that happened 199.6 million years ago.  During this extinction event almost all crurotarsans, therapsides and amphibians were completely wiped out, as well as a significant percentage of marine life.  Although this extinction event was devastated many early megafauna genera, the clade of Dinosauria survived, diversified and dominated for 150 million years.  Life rebounded.

Also, consider the Cretaceous-Tertiary (K-T) extinction event.  The asteroid that struck earth 65 million years ago led to the destruction of all members of the Dinosauria clade that had thrived after the T-J extinction event.  That was a tremendous set back for life on our planet and certainly impoverished the biosphere.  As stated above, the clade Dinosauria had been the most dominant form of life on our planet for over 150 million years, and within the span of a couple thousand years (at the most), they ceased to exist.

But life rebounded, AGAIN (and gave rise to the class Mammalia of which we are a part).

You may now say “But wait… those past extinction events may have occurred suddenly on a geological scale and caused mass impoverishment of the biosphere, but they were caused by natural processes, not by one incredibly destructive species (i.e. Homo sapiens sapiens)”.

That may be true (and again I’m not defending our species for decreasing genetic diversity and causing mass extinction within the biosphere), I am simply making the point that life is resilient.  Life is like a snake that grows two heads if you cut one off.  If you cause the extinction of one branch of the evolutionary tree of life, two or three more will end up occupying the niche that has been left vacant.  And even though we are not like a destructive asteroid event because we are an ever present and persistent force that all other life must deal with – as opposed to a transient force – I believe that the more experience we have as a global species, the better we will become at sustainably managing the biosphere.  During the Columbian exchange we were a young species with no experience, or capacity to organize ourselves on a global scale.  We had no understanding of the evolutionary forces that would cause biological impoverishment on continental scales.

Where Crosby condemns our species for unknowingly impoverishing the biosphere, I give our species a pass.  We did not know any better.

Today, I am less forgiving.

Fifteenth century conquistadors should not be blamed for things they had no idea were happening on a global scale and our species should not have to de-globalize as a penalty for their medieval mistakes.

A good exchange

So my answer to John Green is that the Columbian exchange was worth it.  By globalizing, even though we made mistakes along the way, we increased life expectancy and the quality of life for our species as whole.  This process continues today (see previous blog posts: here and here).  And my thoughts on these questions lead me to advocate for continued progress and development, however this progress and development should always lead to improved life expectancy and quality of life for our species AND must not cause damage to major ecosystems or cause significant reduction to biodiversity.  I am against anything that would lead to the destruction of our planet and the biosphere.

We should be advancing past the stage in our development where that is acceptable.

I want us to learn from our mistakes and improve both morally and technologically.  There is no reason why those two elements of improvement must be mutually exclusive (even if they often have been in the past).



About Cadell Last
Hello. I'm probably drinking coffee and reading.

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