Our bi-annual trip to Little Rock and environs could easily include a stop in Hot Springs. I swung by the Hot Springs National Park there last weekend and really liked the potential of the observation tower as a place to tie in the themes of geography. The town is small enough that you can see it all, including the reservoirs supplying it with water, from the tower. It’s something to consider.
I’ve also just noticed that the National Park Service has, on their Teachers page, a two for one deal where you can visit the Hot Springs National Park and Central High School and have your costs reimbursed. I’m pretty sure, however, that this does not include the tower.
90% of the cells in your body are bacteria and other provocative facts about the Domain Bacteria are the subject of a great but long article by Valarie Brown.
[R]esearchers have also discovered unique populations adapted to the inside of the elbow and the back of the knee. Even the left and right hands have their own distinct biota, and the microbiomes of men and women differ. The import of this distribution of microorganisms is unclear, but its existence reinforces the notion that humans should start thinking of themselves as ecosystems, rather than discrete individuals.
—Brown (2010), in Miller-McCune.
The article makes for great reading during this cycle’s work on classification systems and evolution. One choice paragraph summarizes the fundamental differences between the domains of life:
There’s such ferment afoot in microbiology today that even the classification of the primary domains of life and the relationships among those domains are subjects of disagreement. For the purposes of this article, we’ll focus on the fundamental difference between two major types of life-forms: those that have a cell wall but few or no internal subdivisions, and those that possess cells containing a nucleus, mitochondria, chloroplasts and other smaller substructures, or organelles. The former life-forms — often termed prokaryotes — include bacteria and the most ancient of Earth’s life-forms, the archaea. (Until the 1970s, archaea and bacteria were classed together, but the chemistry of archaean cell walls and other features are quite different from bacteria, enabling them to live in extreme environments such as Yellowstone’s mud pots and hyperacidic mine tailings.) Everything but archaea and bacteria, from plants and animals to fungi and malaria parasites, is classified as a eukaryote.
—Brown (2010).
Brown also gets into a discussion of if bacteria think:
[B]acteria that have antibiotic-resistance genes advertise the fact, attracting other bacteria shopping for those genes; the latter then emit pheromones to signal their willingness to close the deal. These phenomena, Herbert Levine’s group argues, reveal a capacity for language long considered unique to humans.
—Brown (2010).
Trimming this article down would probably make it a good source reading for a Socratic Dialogue.
Bacteria are the sine qua non for life, and the architects of the complexity humans claim for a throne. The grand story of human exceptionalism — the idea that humans are separate from and superior to everything else in the biosphere — has taken a terminal blow from the new knowledge about bacteria. Whether humanity decides to sanctify them in some way or merely admire them and learn what they’re really doing, there’s no going back.
—Brown (2010).
Clarity of thought and the ability to persuade are important life skills that develop as the parts of the brain responsible for analytical thinking develop during adolescence. The persuasive essay is the most common form used to assess these abilities. During this cycle we will work on writing persuasive essays, but it is useful to remember that the pattern of these essays, with their beginning thesis statement, well organized persuasive paragraphs, and concluding statement, can also be used in many other types of presentation.
We can start by considering brain development, because during adolescence the prefrontal cortex matures. Located just above and behind the eyes, the prefrontal cortex is responsible for higher thinking: things like abstract analysis, controlling moods and planning. Not only does this part of the brain get bigger but the way the brain cells, called neurons, are connected also get substantially reorganized. New neural pathways develop as adolescents discover new and more sophisticated ways of thinking about themselves and the world around them.
However, just because the brain develops does not instantly mean we become instantly able to think abstractly. Practice tunes the brain. Repetition is what establishes new neural pathways and makes them bigger and wider.
Yet once we develop these skills, how do we show them to the world? This is where the power of the persuasive essay comes in: arguments require reasoning, logic and deft writing to convince. A good persuasive essay is a tour-de-force demonstration of these higher-level thinking skills. The ability to articulate a clear, straightforward thesis illustrates the ability to integrate disparate ideas. The sequencing of ideas in the paragraphs demands a strict adherence to logic. A beautiful turn of phrase or a description that paints a vivid picture brings the essay to life and captures the reader’s interest and imagination. Beauty appeals to the heart. Logic commands the brain. In combination, the persuasive essay appeals to the key attributes that make us human.
There are, of course, other methods for showing our prefrontal abilities, such as film, dance and oral argument, but these others lack the ease of distribution and the consideration of the audience offered to the reader of the persuasive essay. A simple missive, short and sweet, can be mailed, emailed or hand delivered quickly and efficiently. Furthermore, it places less stress on the reader. A good persuasive essay is necessarily concise; it says only what it has to to make its point. It also offers the reader great flexibility in how to take it in. By skimming the introduction and topic sentences the reader should be able to get the gist of the writer’s argument. Then the reader can choose to be drawn more deeply into the text, or even just an interesting paragraph, by the seduction of elegant prose. The reader can get an essay in myriad ways and can easily plunge into and out of it at will, wallowing in the language or skimming across the tips of the paragraphs.
So while a picture is worth a thousand words, the persuasive essay can convey, not just the ostensible argument on the page or even the message hidden in the subtexts, but the clarity of thought, the abstract thinking skills, and the logical control of the writer herself. A good essay tells as much, or more, about the writer than it does about the topic.
Landforms in the sandbox before and after the rain.
We left the sandbox uncovered under last week’s heavy rain, and the result was a new perspective on erosion, sedimentation and the evolution of landforms.
Nice, sharp, hand-sculpted valleys were smoothed out by the raindrop splatters. The beautifully steep sided fjord on the lower left, in particular, eroded into the gentler slopes of a fluvial surface.
This process is diffusional. Sand moves from high peaks to fill in the low valley floors, evolving toward a softer, flatter land surface in the same way dye in pan diffuses from the high concentration droplet to a more uniform distribution.
There was enough rain that water pooled, for a little while, at the lower end of the sandbox. This allowed the formation of a beautiful little delta from the main river, which was most remarkable to observe while it was raining because the channel bifurcated at its mouth with running water to the left and right of the depositional landform.
Island bluffs surrounded by sandy beaches.
The standing water in the “ocean” also caused the islands to partially erode at the edges to create steep bluffs overlooking sandy beaches.
And finally, if you looked carefully at the sides of the river channel you could see where the water was beginning to cut into the banks, a little offset on either side, to start the formation of meanders.
One of our fish has died. With permission, I’ll let Sage Beasley, the main instigator of the fish tank explain (she does it much more elegantly than I could):
A few weeks ago one of our fish died. Its name was It’s A Fish. I liked the fish. I had gotten him for a Natural world experiment and when we were done with it I put him in a tank at school with the other fish It’s A Whale. It’s A Whale is still alive and healthy. We found a religion for [It’s A Fish] (he’s Norse) and followed their ritual to send the fish into the next life. We put it in a paper boat with vegetable oil and set it on fire. We have released the fish’s spirit to where ever it goes next.
– Sage Beasley (2010), in the Middle School Newsletter.
I’ll just note that every middle school should have a sandbox/watertable.
One of the easiest and most elegant ways of explaining the classification of organisms, the history of life on Earth, and the relationships between different organisms is to construct a phylogenetic tree. I have a great exercise I like that takes just some bits of colored paper, string, a poster board and some thumbtacks.
To start, each student writes the Latin domain, kingdom, phylum, class, order, family, genus and species names on separate pieces of colored paper. I hand out paper in stacks and give them strict instructions not to rearrange the order of the colors. Wikipedia is actually a great resource for this because they tend to be quite reliable on this if they have the specie you’re looking for (and they have quite a bit).
Students then tape the pieces of paper together on a string, species at the bottom, domain at the top, and, one by one, tack them to the poster board. As each student attaches their string to the board they say the common name of their organism and then recite the phylogeny.
When I did the exercise on Monday, I asked the students to use the organisms they’re working on for their independent research projects so everything started with the domain Eukaria. Interestingly enough, the Wikipedia pages don’t have the domain classification, probably because they think it’s too obvious, but I had a number of kids spend quite a bit of time trying to figure it out; they probably benefited from doing so I didn’t mind at all.
Constructing the phylogenetic tree.
Classifications that are the same are tacked one on top of the other, Eukaria on top of Eukaria, Mammalia on top of Mammalia and so on, so that, as students add their parts of the phylogeny, you begin to see the phylogenetic tree. We had insects, mammals, plants and reptiles, so there was quite a nice variety represented.
After about half a dozen lineages were on the board, the procedure began to get a bit repetitive, so I started to ask students to guess, based on the common name, where the next species to go on would diverge from the rest of the emerging tree. Students seemed to like this part of it. I had started with homo sapiens when I demonstrated the procedure so it was salutary for them to see how much the other organisms differed from humans.
When everything is tacked on, you end up with a cute picture of a the tree of life that makes a cute, but awfully real looking, phylogenetic tree. Students tack their pieces of paper on the string at different distances, some much closer together than others. As a result, the final tree is looks as though it shows the genetic divergence between the different groups. It a fake, but lends a sense of verisimilitude non the less.
We’ve discovered committees. Yesterday, after spending half an hour discussing the brand new bread bag prototype that one of the students came up with, they decided that maybe just the people interested in working on them should work on them. So we just, organically, created a committee.
As with all new discoveries we’re now using them for everything. Today the students decided on a committee to run Dinner and a Show. We’ll see where this goes.
WritingDEN‘s Tips-O-Matic is a great site on writing great paragraphs and essays. The pages are very simple and well organized, without all the distracting noise of ads and extraneous information.
The language curriculum focuses, in general, on developing good writing style and craft, but some of my students need to work on the basics of essays a bit more, particularly with high-school entrance essays coming up.
