Germs Seeds and Animals



In history classes, students struggle to memorize and regurgitate the names, dates, and places essential to our glorious myth — the sacred journey that brought us to the miracle of today.  For many, this parade of dusty factoids is the story they will believe for the rest of their days.  What I was taught about Christopher Columbus resembled a kindergarten fairy tale — the courageous hero succeeds.  Hooray!

The last 50+ years have released a flash flood of important new information.  Our planet is being disemboweled by seven-point-something billion humans racing down a hell-bound path for no good reason.  Alfred Crosby was an important pioneer in the field of environmental history.  In his book, Germs, Seeds, and Animals, Crosby described how the Columbus voyage of 1492 detonated a global ecological catastrophe.  It was a monumental event in the human saga, something like an asteroid strike.

When the Pilgrims washed ashore at Plymouth Rock in 1620, they were not immediately exterminated by Wampanoag warriors, because the tribe was nearly extinct.  Smallpox got there first.  Pilgrims found an empty village surrounded by cornfields full of weeds.  During the first winter, half of the colonists died from malnutrition, exhaustion, and exposure.  They knew almost nothing about surviving in a foreign ecosystem.  Pilgrims struggled to survive on shellfish, and on corn (maize) that was bought or stolen from the Indians.  It wasn’t until 1624 that they figured out how to live on their own.

Native Americans were spooked by the freaky aliens.  Everyone around them was dead or dying, while none of the aliens were molested by evil spirits.  Deadly diseases, especially smallpox, spread from tribe to tribe, across vast regions, well in advance of explorers and settlers.  Natives could have easily exterminated the Pilgrims, but they were fearful of their horrific dark powers.  Without smallpox, history could have taken a radically different path.

The Pilgrims came from a densely populated civilization that had transformed its thriving rainforest into fields, pastures, and disease-ridden cities.  In Europe, smallpox had raged for centuries.  Around 1500, the virus mutated into a far more virulent form, killing many children in cities near the Atlantic coast of Europe.  Folks who survived to adulthood were those lucky to have unusually robust immune systems.  It was these folks who carried smallpox to the New World in 1518, where it killed up to half of those infected.  The virus could unintentionally be transported via a trunk of clothing.  Human-to-human contact was not needed.

In an era of long distance sea travel, ships often returned to Europe with new and exciting diseases from every corner of the Old World.  Many deadly diseases originated in domesticated animals, with whom Old World people often lived in close contact.  A number of livestock pathogens were able to transfer to human hosts.  These germs especially loved infecting dense crowds in filthy cities.  Epidemics of assorted diseases bounced from region to region on a regular basis.  Native Americans, who did not enslave herds of animals, had only two indigenous pathogens, Chagas’s disease and Carrion’s disease.

Spaniards documented the die-off in Mesoamerica (Aztecs) and Peru (Incas), where 90 percent of the Native Americans were dead within a century.  In these cooler highland regions, folks died from temperate diseases, primarily smallpox, measles, whooping cough, and pneumonia.  In the hot, wet coastal lowlands, people not only died from temperate diseases, but also tropical diseases, like malaria, yellow fever, dengue fever, and amoebic dysentery.  Around 1590, an observer estimated that 29 of every 30 lowland natives had perished from disease.  As a special bonus, Europeans also brought chicken pox, typhus, typhoid fever, bubonic plague, cholera, scarlet fever, diphtheria, and influenza.

To this day, Old World diseases continue killing natives who come into contact with outsiders for the first time — missionaries, loggers, miners, etc.  By far, the primary reason Europeans conquered the Americas was disease.  I was surprised to learn that Europeans did not intend to exterminate the natives and replace them with settlers.  Colonists suffered from get rich quick fever, and the fast path to wealth was to control and exploit multitudes of Indians.

Unfortunately, the native workers rapidly died from disease, malnutrition, and abuse.  This labor shortage inspired a rapid expansion of the highly profitable slave trade.  Africans were less vulnerable to the tropical diseases, for which white folks were helpless sitting ducks.  At least ten million slaves arrived alive in America.  Millions more perished before setting foot ashore.  Once here, their death rate was higher than births, which kept the slave industry booming.

Old World livestock thrived in the New World.  The new ecosystem had abundant vegetation, was free from Old World pathogens and parasites, and wild predators were not a serious threat.  Animals grew faster and larger, and had more offspring.  On the pampa of South America, where few humans lived, feral horses and cattle multiplied into huge populations — they had no buffalo to compete with.

Corn (maize) was a super-productive crop.  Sowing a bushel of wheat might yield 12 to 20 bushels at harvest time.  A bushel of corn might yield 200 bushels or more.  Corn could be grown using simple tools and unskilled labor.  It could be grown on marginal soils, required minimal weeding, and could survive several frosts.  It stored well.  Husks discouraged losses to birds.  When mature, ears could be left on the stalk and harvested later, without risk of spoilage.

Settlers in America were far better nourished than the sickly mobs of Europe.  Most lived in rural areas, in low density, which discouraged epidemics.  They bred like crazy, and many of their kiddies survived to adulthood.  Folks had access to abundant land for expansion.  By 1775, the U.S. population was doubling every 25 years.  In 1790, half of Americans were younger than 16 years old.

Meanwhile, Europeans took corn, potatoes, and treasure back to the Old World, where they blindsided almost everything.  Corn became a staple in southern Europe.  For many folks, it was their primary food.  Because it lacks the essential nutrient niacin, many poor folks came down with pellagra.  Around the world, in the eighteenth and nineteenth centuries, hundreds of thousands died from pellagra.  The simple cure was a slightly better diet.

Potatoes were widely adopted in northern Europe, where they produced far more nutrients per area than traditional grain crops, which were vulnerable to molds, fungus, and cool weather.  A family of five could survive on 5 acres (2 ha) of grain, or just 1.5 acres of potatoes.  Folks remained healthy on a daily diet of 11 pounds (5 kg) of potatoes and some milk (another source said 10 pounds).  Potatoes contained vitamin C, so far fewer died from scurvy during winter months.  Farmers could raise them on marginal soils, using only a spade.  In wartime, invaders could easily steal stored grain, but buried spuds were often too much effort to swipe, so fewer farmers starved.

Gold, silver, and gems were hauled back to Europe.  This provided a flash flood of new wealth, which greatly expanded the global economy.  Manufactured stuff went to the New World, and resources sailed back to Europe.  The wealth surge provided the capital needed to jump start the Industrial Revolution. 

Because potatoes and corn were highly productive, less cropland was needed.  So, many peasants were forced off the land, to make room for sheep, which generated more profit.  Mobs of displaced people migrated into cities, where they provided cheap labor for industry.  After the 1666 epidemic in London, the plague largely went dormant in Europe.  This spurred population growth, which intensified urban filth, and provided ideal conditions for the cholera epidemic that arrived in 1829.

Aided by potatoes and corn, both Europe and America were able to harvest far more food.  People were better nourished, so child mortality dropped.  The population of Europe leaped from 80 million in 1492, to 180 million in 1800, and 390 million in 1900.  Europe was bursting with people, and many migrated to colonies — Australia, New Zealand, southern Brazil, Uruguay, Argentina, Canada, and the U.S.  Bottom line, world population leaped from 450 million in 1500 to 7.5 billion in 2018.

Crosby concluded that Columbus sparked “the greatest demographic catastrophe in the human record.”  “The encounter may have been the most influential event on this planet since the retreat of the continental glaciers.”  “Calories can make as much history as cannons — more in the long run.” 

Crosby, Alfred W.  Germs, Seeds, and Animals: Studies in Ecological History, M. E. Sharpe, Armonk, New York, 1994.

Other Crosby books I’ve reviewed are Children of the Sun, and Throwing Fire.

Potato

The wild potato is a masterpiece of evolution.  Botanists have discovered 169 species of them, widely dispersed across the Americas, but primarily located in the Andes.  Wild spuds have been able to adapt to every type of ecosystem except for lowland tropical rainforest.  Their foliage is bitter with toxic glycoalkaloid compounds that promptly spoil the appetite of hungry leaf munchers (or kill them).

Beneath the ground, small tubers grow on the roots, in a wide variety of colors and shapes.  The toxic tubers store energy and moisture as insurance against unfavorable conditions.  As they mature, the plants flower, and then produce tomato-like fruits containing up to 200 seeds.  Because the seeds are the result of sexual reproduction, each one is genetically unique.  Some will be resistant to frost, and/or drought, and/or blight.  Wherever they happen to grow, plants having the most suitable genes for local conditions will be the most likely to thrive and reproduce.  Diverse genes are essential for long-term survival.

Wild spuds are not the slightest bit interested in sprawling agribusiness monocultures, cancerous civilizations, population explosions, fungicide industries, topsoil destruction, or morbid obesity.  They simply find ways to blend into their ecosystem, live well, and not rock the boat, like all proper and dignified organisms do.

After consuming several tons of domesticated spuds over many decades, John Reader was inspired to write Potato, a highly readable book that described the amazing success of the humble spud, and the astonishing unintended consequences.  It adds one more chapter to the ongoing comedy of backfiring human cleverness.

Nobody has come up with a compelling explanation for why humans domesticated toxic little tubers, but we did.  Some of the myriad mutants resulting from wild potato sex must have produced tubers with low toxicity that tickled the imagination of somewhat-clever minds. 

Domesticated tubers are much larger than wild ones, and much better tasting.  When the plants stop growing, and the foliage withers, the tubers are no longer poisonous.  An acre of spuds can produce as much food as eight acres of wheat — in much less time.  Spuds are now our fourth most common food, following wheat, corn, and rice.

They are remarkably nutritious.  You can eat nothing but spuds for several months and remain healthy.  If you add a glass of milk to every meal, you will be completely nourished — this was the Irish peasant’s diet 200 years ago.  The average adult male ate 10 pounds of spuds daily, and 20 when working hard.  Seriously!

Potatoes can thrive where grains don’t, and they can be stored for months.  Long ago, the people of the Andes learned how to make chuño — freeze-dried potatoes, which can be stored for years, while losing no nutritional value.  Sweet potatoes are not related to potatoes, and they spoil far more quickly.

Prior to the arrival of potatoes, European peasants were typically malnourished and short-lived.  But spud-gobbling bumpkins were healthy and vigorous, despite their extreme poverty.  Potato-fed kids were more likely to survive into adulthood and reproduce.  Infants could be weaned earlier by switching them to a mix of mashed potatoes and buttermilk, allowing mom to get pregnant again sooner, and have more children.  When potatoes arrived in Ireland around 1600, the population was no more than 1.5 million.  By 1845, it was 8.5 million, of which 90 percent were hardcore spud addicts.  This explosive growth could not continue, of course.

I shall now introduce the arch villain in this story: Phytophthora infestans, a fungus commonly referred to as “late blight.”  It probably originated in the highlands of central Mexico, and then migrated to other regions.  Today it can be found almost everywhere, and wet weather is its call to action.  Blight spores can ride the winds to new locations.  Nothing gives it greater pleasure than discovering a big field of moist mature potato plants.

In 1845, spores from the US took a steam ship cruise to Ireland, where everyone was eagerly expecting a bumper crop of lumpers.  To their horror, entire fields turned black overnight.  Blight raced across Europe, destroying two million square kilometers in four months.  It struck again in 1846 and 1848.  Ireland was hit hardest, and their wretched British overlords could not be bothered to provide much assistance.  A million Irish died, and a million emigrated.

I shall now introduce the hapless victim in this story: Solanum tuberosum, the family of domesticated taters.  In the process of being transformed from wild toxic tubers to an incredibly productive super food, domestic spuds lost most of their sex drive (via male sterility).  Few produce any fruits or seeds.  So, commercial American potatoes are not grown from “true seeds.”  Instead, farmers plant “seed tubers,” which are hunks of tubers from the last harvest.

True seeds are rugged survivalists, because they are genetically diverse.  But domesticated potatoes are helpless sitting ducks, because they are genetically identical clones.  If one is susceptible to blight, they all are.  Reader says, “In fact, most modern cultivars are biological ‘monsters’ that could not survive in the wild.”  They can’t live without human caretakers (like domesticated dogs, cattle, sheep, and maize).

Scientists have two control options.  The cheapest solution is to breed new varieties that are blight resistant, but this is a time-consuming process, and there are only a limited number of gene tricks that work.  The success of any new variety can only be temporary, because the blight fungus is constantly mutating.  Blight will inevitably create offspring that can overcome the resistant spud’s defenses, and each new blight spore can produce 100,000 spores in four days.  The scientists will have to start all over again.

The other solution is more expensive and toxic: fungicides.  In wet seasons, a field might be sprayed 12 times (or 30 times in super-moist New Guinea).  Like plant breeding, the effectiveness of fungicides is temporary, because the fungus will inevitably develop resistance to them.  When one poison stops working, you switch to another, use more, or try combos.

There can be no permanent solution to blight.  Scientists will run out of clever tricks long before Mother Nature quits producing countless new fungus mutants every minute.  Rising energy costs will continue to drive up the price of fungicides, making them unaffordable for a growing number of poor farmers.

Wild spuds still thrive in the high Andes, preserving the wild gene pool that’s essential to the work of plant breeders.  Blight has never been a problem in this region — until recently.  Climate change has been making the weather warmer and wetter in the homeland of spuds.  Some crops of native potatoes have been heavily damaged.

The venerable historian William H. McNeill once penned an essay titled “How the Potato Changed the World's History.”  Europe’s population skyrocketed between 1750 and 1900, thanks in part to the spud.  Millions of surplus country folks were forced to move to cities, work in factories, earn peanuts, and live on taters.  Thus, spuds played a significant role in the mass emigration of Europeans, the growth of colonial empires, and the rise of Russia and Germany as industrial powers.

Reader lamented that “millions [of] lives were spent as fuel for the Industrial Revolution,” but in its wake, “a new and better world emerged.”  Really?  I have a feeling that it would have been wiser to leave the spuds as we found them — wild, free, and happy.

This book has many, many more spud tales to tell.  Throw some French fries in the microwave and find a comfy chair.

Reader, John, Potato — A History of the Propitious Esculent, Yale University Press, New Haven, 2009.