Study Questions for Jared Diamond, Guns, Germs and Steel, Chapter 10

1) Quick review:  Summarize in 1 sentence the findings of the last reading (chapter 8).
"[I]ndigenous crops from different parts of the globe were not equally productive.""When compared to the natural suite of the Fertile Crescent's biological organisms, both the New Guinea and eastern North America possessed some decisive disadvantages in their suites of domesticable plants and animals."

"Food production's spread proves as crucial to understanding geographic differences in the rise of guns, germs, and steel as did its origins" (p. 176)

2)  OK.  This chapter is about diffusion of domesticated plants and animals.  It looks like Diamond answered all the important questions in chapter 8.  But he still has a hard task to answer Yali's question about the different rates of development among different peoples.  Let's start with the basics.  What are the axes of orientation among the world's major continents?
Eurasia has an E-W orientation, while Africa and N and S America have a N-S orientation.  Rates of diffusion along these axes differed significantly:
SW Asia to the east and west .7 mpy
New World .2-.5 mpy

3)  Reduce the entire chapter to a single sentence that compares East-West diffusion and North-South diffusion.
Diffusion of crops and livestock, and possibly also of writing, wheels, and other inventions along Eurasia's E-W axis orientation was rapid because of latitudinal-environmental similarities. Latitudinally similar locations share the same day length and roughly similar climates. Germination, growth and disease resistance are adapted to these factors.  N-S diffusion was slow or non-existent because of the wide range of latitudinal-environmental differences.

Main paths of food production diffusion.
SW Asia to Europe, Egypt, North Africa, Ethiopia, Central Asia, Indus Valley
Sahel and W. Africa to E. and S. Africa
China to tropical SE Asia, Philippines, Indonesia, Korea, Japan
Mesoamerica to North America

4)  The ease of EW diffusion (in contrast to NS) is clearly made in the parable of the Canadian farmer.  What was the point of that story in relation to the growth cycles of plants.
Low latitude plants are "poorly adapted to to high-latitude conditions"  because low latititude plants are adapted to germinate in spring and to grow at a leisurely  rate. These plant adpatations would be lethal in high-latitude (cold areas with short growing seasons) areas.  They also would lack "resistance to diseases of high latitudes."

Slow spread (America) often led to multiple domestications of same plant (cotton).
Rapid spread (SW Asia) resulted in single domestication of plant, Diamond calls this preemptive domestication.

5)  Why didn't the Pilgrims immigrate to the Amazon?
They didn't take a left turn in the middle of the Atlantic Ocean.  Seriously, Europeans generally colonized those places with a roughly similar climate—North America, Australia, and South Africa.

6)  Other than length of day, what inhibited crop/animal diffusion in Africa?
The Sahara Desert and sub-Saharan tropics acted as barriers. Tsetse flies  hampered the diffusion of livestock. As a consequence, food and animal domestication happened very slowly, sometimes not at all, in southern Africa.

7) Other than length of day, what inhibited crop/animal diffusion in the Americas?
Mexican and Andean crops could have been interchangeable. Mexico could have raised South American llamas, guinea pigs, and potatoes.
The Andean peoples could have raised Mexican corn.  And they did, but it was relatively late. Central America's tropical lowlands prevented the diffusion.  North America's Great Plains also served to bar rapid northern and eastern diffusion from Mesoamerica.

8) Diamond ends his discussion with a brief word about the wheel.  Clearly, a wheel doesn't respond to differences in day length or tropical lowlands.  What point is he making then?  Hint--this example makes a link to the "proximate" factors that we are about to discuss:  namely, germs, technology, and politics.
A wheel does not respond to differences in day length or tropical lowlands.  However, Diamond points out that "societies that engaged in intense exchanges of crops, livestock, and technologies related to food production were more likely to become involved in other exchanges as well."  Diffusion of crops/animals from Mesoamerica to the Andes.  Therefore, why would Mesoamerica's wheel diffuse?  There was no pattern of diffusion between these two regions.

Study Questions for Jared Diamond, Guns, Germs and Steel, Chapter 11

1)  Sorry about the story at the start of this chapter.  But Diamond is trying to make a point.  What is it?
Humans in regular, close contact with domesticated animals can pick up infectious diseases from them, and develop permanent or temporary immunity (antibodies vs. antigens) to some of those diseases. "The major killers of humanity throughout our recent history-smallpox, flu, tuberculosis, malaria, plague, measles, and cholera-are infectious diseases that evolved from diseases of animals."

2)  Does this chapter present a proximate or an ultimate explanation for Yali's question?  Explain.
This chapter presents a proximate explanation for Yali's question.  The chapter explains the emergence of germs, disease, and immunity to disease, that were caused by food production (an ultimate cause).

3) Why do diseases make us sick (cough, diarrhea)?
Coughing and diarrhea allow disease-causing microbes to be spread widely and rapidly to new hosts.  Coughing (influenza, common cold, pertussis); Diarrhea (cholera)

4) What is a necessary ingredient for epidemic diseases like measles, mumps, rubella, and smallpox?  Quick, can you connect the answer of this question to the "power of farming"?
Epidemic diseases have 4 characteristics: 1) Quick spread throughout whole population; 2) They are acute.  You either die or recover quickly; 3) Survivors develop long-term immunity; 4) Microbes that cause epidemic diseases are restricted to humans. 
Measles, mumps, rubella, and small pox need large host populations so that they have sufficient hosts while they wait until a sufficient population of babies have been born to serve as new hosts. Ex: Measles requires 500,000 population not to die out.  "Crowd diseases could not sustain themselves in small bands of hunter-gatherers and slash-and-burn farmers."  So microbes that might have infected European explorers could not develop in small populations.

5)  Explain how city folks are exposed to "crowd diseases." 
Early cities had higher population densities with worse sanitary conditions than rural areas.  These cities represented larger, more closely packed crowds of hosts for microbes.  "Not until the beginning of the 20th century did Europe's urban populations finally become self-sustaining: before then a constant immigration of healthy peasants from the countryside was necessary to make up for the constant deaths of city dwellers from crowd diseases."

Explain how farmers are exposed to the same diseases.
Farmers are sedentary living among their own sewage.  Some farmers gather human waste to use as fertilizer.  Irrigation can spread infected water.  Rodents (disease vectors) are attracted to stored food.  Forest clearings and pooled water creates mosquito habitat.

5a)  This is an important connection.  Describe why the plague was so successful, using what you have learned from Diamond, especially his thoughts on the importance (ease of spread) of the east-west axis.
The bubonic plague travelled westward from Central Asia along an overland trade route that linked China with Europe.  This route followed the E-W axis along which domesticates diffused thousands of years earlier.  Intensive E-W exchange developed along this axis and allowed fleas, disease vectors, from Central Asia to travel this axis in furs that were traded in Europe.

6)  Diamond remarks that when he was a student in high school, he had learned that there were only about 1 million Native Americans in the New World.  What, in his estimation, did this justify? The white conquest of an "empty" continent.  Do we play similar games with numbers today?  Think of the widely diverging estimates of the number of people at the New York City protests.

7)  Give the two most important reasons for the failure of epidemic diseases in the New World.
~There was a lack of large, domesticated mammal populations in the New World to serve as "wild starting material" for epidemic microbe evolution.

~Late development of centers of high population density, which were linked by "regular, fast trade" meant that there was no long-term breeding ground for epidemic microbes. 

8) Where do we find such diseases as malaria and yellow fever? 
Initially, malaria was found in the Old World tropics.  Colonization (slave trade) spread it to the New World tropics.  Initially, yellow fever (a disease whose microbes maintain themselves in wild monkeys) was found in the African tropics.  Colonization (slave trade) also spread it to the New World tropics. 

How did these diseases impact the history of European colonization?
Malaria and yellow fever delayed European colonial expansion in the Old World tropics (Africa and New Guinea especially), and once these diseases diffused to the New World tropics, they hampered colonization.