Drought on the Mississippi

Last summer’s drought, and more weather extremes probably due to large-scale global climate change, is having dire effects on shipping on the Mississippi River. Suzanne Goldenberg has an excellent article in the Guardian.

Students look upstream at the Missouri River from the Melvin Price lock and dam, just north of St. Louis, and close to its confluence with the Mississippi River. The dam is tasked with maintaining about 9ft of water in the river for shipping.

Shipping companies say the economic consequences of a shutdown on the Mississippi would be devastating. About $7bn (£4.3bn) in vital commodities – typically grain, coal, heating oil, and cement – moves on the river at this time of year. Cutting off the transport route would have an impact across the mid-west and beyond.

…

Farmers in the area lost up to three-quarters of their corn and soya bean crops to this year’s drought. … Now, however, [they] are facing the prospect of not being able to sell their grain at all because they can’t get it to market. The farmers may also struggle to find other bulk items, such as fertiliser, that are typically shipped by barge.

— Goldenberg (2012): Mississippi river faces shipping freeze as water levels drop in The Guardian.

The proposed solution is to release more water from the Missouri, however there would be a steep price to pay.

The shipping industry in St Louis wants the White House to order the release of more water from the Missouri river, which flows into the Mississippi, to keep waters high enough for the long barges to float down the river to New Orleans.

…

Sending out more water from the Missouri would doom states upstream, such as Montana, Nebraska, and South Dakota, which depend on water from the Missouri and are also caught in the drought.

“There are farmers and ranchers up there with livestock that don’t have water to stay alive. They don’t have enough fodder. They don’t have enough irrigation water,” said Robert Criss, a hydrologist at Washington University in St Louis, who has spent his career studying the Mississippi. “What a dumb way to use water during a drought.”

Assessment with the Toilet Paper Timeline of Earth History

With a larger class, and quite a bit of space in the gym, I had more flexibility working on the toilet paper timeline compared to the last time.

Labeling the timeline in the gym.

I built in a friendly race to see which group could find a set of events first, and allowed me to highlight nine different, important, series of events along the timeline.

The adapted spreadsheet, racing sequences, and a short summative quiz are on this Toilet Paper Timeline spreadsheet.

I broke the class up into 4 groups of 4, and each group created their own timeline based on a handout.

Groups of students lay out their toilet paper timelines. Post-it notes were used to label the events.

Then, I gave each group a slip of paper with four events on it (one event per student), and they had to race to see which group would be first to get one person to each event on the list. Once each group got themselves sorted out, I took a few minutes to talk about why the events were important and how they were related.

Table 1: The series of events.

1) We’ll be talking about plate tectonics soon, so it’s good for them to start thinking about the timing of the formation and breakup of the supercontinents.
Event 1 Event 2 Event 3 Event 4
Formation of Rodinia (supercontinent) Breakup of Rodina Formation of Pangea Breakup of Pangea
2) This sequence emphasizes the fact that most free oxygen in the atmosphere comes from ocean plants (plankton especially), and that a lot of free atmospheric oxygen was needed to to form the ozone layer which protected the Earth’s surface from uv radiation, which made the land much more amenable to life. Also, trees came way after first plants and oxygen in the atmosphere.
Event 1 Event 2 Event 3 Event 4
First life (stromatolites) Oxygen buildup in atmosphere First land plants First Trees
3) Pointing out that flowering plants came after trees.
Event 1 Event 2 Event 3 Event 4
First life First land plants First trees First flowering plants
4) The Cambrian explosion, where multicellular life really took off, happened pretty late in timeline. Longer after the first life and first single-celled animals.
Event 1 Event 2 Event 3 Event 4
First life (stromatolites) First animals First multicelled organisms Rise of multicelled organisms
5) Moving down the phylogenetic tree from mammals to humans shows the relationship between the tree and evolution over time.
Event 1 Event 2 Event 3 Event 4
First mammals First Primates Homo erectus Homo sapiens
6) More tectonic events we’ll be talking about later.
Event 1 Event 2 Event 3 Event 4
Opening of the Atlantic Ocean Linking of North and South America India collides with Asia Opening of the Red Sea
7) Pointing out that life on land probably needed the magnetic field to protect from the solar wind (in addition to the ozone layer).
Event 1 Event 2 Event 3 Event 4
Formation of the Earth First life Formation of the Magnetic Field First land plants
8) Fish came before insect. This one seemed to stick in students’ minds.
Event 1 Event 2 Event 3 Event 4
First Fish First Insects First Dinosaurs First Mammals
9) Mammals came before the dinosaurs went extinct. This allowed a discussion of theories of why the dinosaurs went extinct (disease, asteroid, mammals eating the eggs, volcanic eruption in Deccan) and how paleontologists might test the theories.
Event 1 Event 2 Event 3 Event 4
First Dinosaurs First Mammals Dinosaur Extinction First Primates

The whole exercise took a few hours but I think it worked out very well. The following day I gave the quiz, posted in the excel file, where they had to figure out which of two events came first, and the students did a decent job at that as well.

Why Diversity is Important

Diversity has been a recurring theme this semester. It started with the diversity conference our middle schoolers attended earlier this year, which, unfortunately, I’m not sure they got a lot out of. As a result, I’ve been making a little bit of a point to bring up the subject when it intersects with our work. This week were were talking about evolution and natural selection, as was able to talk about the practical advantages of both genetic and social diversity.

When the environment changes, species don’t usually have time to adapt. Instead, individuals who already have the genes for beneficial existing traits — traits that work well under the new conditions, like the ability to survive warming climates — will tend to breed more, and over the generations, more and more of the population will have the advantageous trait.

Therefore, to ensure the continuation of the species, we’ll want to have the maximum amount of genetic diversity.

Then I tacked. I asked if anyone was not interested in seeing the continuity of humanity, and the usual wags piped up to say that they could take homo sapiens or leave it. So I showed them the Voluntary Human Extinction Movement website. VHEMT advocates that people voluntarily stop having kids so that humanity eventually will become extinct, restoring the Earth’s environment to a healthy state. Their motto is, “May we live long and die out.”

The class was pretty uniformly aghast.

I particularly like the VHEMT website because it’s really hard to tell if they’re serious or not; which drove my students a little bit crazy. And I eventually got the key question I was angling for, “How could anyone want humans to go extinct?”

My response was, for them at least, quite unsatisfactory, because I chose to answer with a different question: “Do you think that diversity of thought is good?”

For some, their answer was no. However, I then reminded them of that first amendment to the U.S. constitution has to do with freedom of expression, which does seem to suggest that the founders thought diversity of ideas was a good thing. Just like species, countries with greater diversity of ideas are more likely to be able to adapt to changing conditions and succeed.

The application of evolutionary theory to social situations has, historically, been fraught with abuse (see the eugenics movement in particular). I also did not have time to bring the conversation back to why we might want to protect biodiversity. However, this particular lesson gets the point across that diversity has some important practical benefits that might not always be obvious.

Notes

An interview with VHMET on the Discovery Channel:

Semi-artificial Selection?

Just like drug resistant germs (we’ve discussed earlier), the rats are evolving.

“They’ve also mutated genetically and are bred to be immune to standard poisons.

“We have had to start using different methods such as trapping and gassing, which can be less effective and more costly.”

–Graham Chappell, from Rapid Pest Control in Newbury in Rowley (2012): Home counties demand stronger poison to deal with mutant ‘super rats’ in The Telegraph.

Homework or Not?

The Finnish and South Korean educational systems are ranked number one and two in the world, yet they’re at opposite ends of the homework assignment spectrum. Louis Menand elaborates:

Students [in Finland] are assigned virtually no homework; they don’t start school until age seven; and the school day is short.

[South Korean schools] are notorious for their backbreaking rigidity. Ninety per cent of primary-school students in South Korea study with private tutors after school, and South Korean teen-agers are reported to be the unhappiest in the developed world. Competition is so fierce that the government has cracked down on what are called private “crammer” schools, making it illegal for them to stay open after 10 P.M. (though some attempt to get around this by disguising themselves as libraries).

— Menand (2012): Today’s Assignment in The New Yorker.

via The Dish.

Empathy

Empathy is seeing the world through the eyes of others. Adolescents tend to look inward, not outward, but empathy is the basis of morality, so exposure to others and other points of view is an important element of their education. I find the following video interesting (much like the Bright Eyes video) because in its hints at so many hidden messages and meanings. It provokes thoughts about who these kids are, what is life like for them, and how do they see the world.

Note: David Brooks argues that while empathy orients one toward moral behavior, it’s really sacred moral codes that convert that orientation into action.