Defense Against Dark Information -- Assignment for Oct. 15
Reading assignment (the tragedy of the commons)
Read the following, available in the Reserves section of Shields
Library or in my office (Plant Environmental Sciences 1312), by next
week. Estimated reading time (in a quiet place without interruptions): 35
minutes, but allow at least an hour so you have time to think
about what you read and to answer the questions below.
- "The Tragedy of the Commons." This title is so well-known, it is
sometimes quoted (like some Shakespeare quotes) without explicit
citation of the original paper. Even after I crossed out some sections that are
less relevant to course themes, to save reading time, this paper
contains several ideas which (if correct!) have important implications
for several different course themes: 1) human population growth, an
important factor driving various trends, 2) cooperation among humans
(key to successful defense against dark information), and 3) evolution
of virulence or benevolence in microbes. You can download a clean copy
from the web at http://www.jstor.org/browse under General Science /
Science vol.162:p.1243 or many other places on the web (but I've seen
versions edited to remove discussion of overpopulation, the author's
- "On human population growth." Watch for points relevant to
several previous readings.
- "Fertility volatility"
- "Population, economics, environment, and culture: an introduction
to human carrying capacity." This article summarizes some key points
from Cohen's book, which is one of the more informative and balanced
discussion of human population questions. At least read the first page
and look at Figure 2 (what are the implications of the "constant
fertility" curve? Fig. 1B is also interesting. Read the rest if you
- "Legume sanctions and the legume-rhizobia mutualism." Is this the
solution to the tragedy of the bacterial commons? Only the first
paragraph is assigned.
- "Evolutionary progress and levels of selection." Depending on
your biology background, parts of this paper may be confusing, but I
hope you will understand some of it. Meiosis and syngamy are the key
steps in sexual reproduction (e.g., production and union of sperm and
egg). Think about tragedies of the commons at each evolutionary stage
discussed. A book, "The Major Transitions in Evolution" is a more
up-to-date and detailed treatment
- "Evolution of cooperation and conflict in experimental bacterial
populations." Experimental data relevant to one of the transitions
hypothesized in the previous paper. I am only assigning the first
paragraph (in bold type), but read the whole thing if you have
time. In this case "cooperation" means spending resources to produce
chemicals that help a group of neighboring bacteria to stick together
and float rather than sink. This paper also cites some of the most
important papers in the scientific literature of cooperation, including
the previous one.
Reading questions -- written answers due at beginning of class:
1) Hardin quotes Darwin's grandson on ongoing human evolution. How
long did C.G. Darwin suggest that the changes that concerned him might
2) Sandvik refers to the three factors that determine "a trait's
per-generation response to selection" (i.e., the rate of evolution of
that trait, i.e., the rate at which its frequency in a population
changes over generations). What are those three factors?
3) In the "Fertility volatility" paper, how do differences among
groups mentioned compare to changes since 1950?
4) When Cohen says "the facts should immunize you", what kind of
replicator is he offering to protect us against?
5) In the paper by Kiers et al., what did defectors fail to do and
what happened to them?
6) If the cells within a plant or animal competed against each
other, what fundamental "privilege" would they compete for, according
to Maynard Smith?
7) In the paper by the Rainey's, what did "defecting genotypes" fail
Questions to think about (to be discussed
- This week's readings discuss two main questions: 1) how worried
should we be about human population growth, and 2) does sustained
cooperation (among humans or among microbes) require some kind of
coercion or sanctions? The size and the density (people per acre) of
human population can affect the rate of evolution and dispersal of
dangerous microbes. Perceptions that population growth is "out of
control" could perhaps lead to risky attempted "solutions." Cooperation
among humans is one key to reducing the dangers from rampaging
replicators. Various forms of cooperation among microbes may
determine whether they are helpful or harmful to humans or crops.
- What do you think are the most important points from Hardin's
paper? For each, point, do you think he is: 1) right, 2) wrong, or 3)
right in some sense, but misleading, so the information is likely to be
misinterpreted or misapplied? Information or insights in the other
papers are also relevant to this question.
- If we want microbes to evolve to be beneficial rather than
harmful, what conditions would we need to create? We will discuss this
topic again with specific reference to human pathogens, after some