On Rabbit Digestion

rabbit-poo — Figure 1. Undigested fiber from rabbit fecal pellets.

One of my favorite things is when my students teach me something I didn’t know. One of those things is that rabbits eat their own poop.

Well not exactly. According to Dana Krempels, from the University of Miami, rabbit fecal pellets (poop) are different from the other type of droppings that lagomorphs actually eat, which are called cecotropes (Kempels, 2010; Rabbits: The Mystery of Poop). Cecotropes apparently have lots of helpful bacteria and nutrients. Rabbits that don’t get to eat them tend to suffer from malnutrition.

rabbit-pellets — Figure 2. Rabbit fecal pellets, with one mostly dissected, in a standard petri dish.

Independent Research Project

For her Independent Research Project (IRP) this term, one of my students researched rabbits, and, as was required, tried to find them on our nature trail. She found indirect evidence. Small fecal pellets in the grassy area next to the trail’s exit, just where her research said they might be (which was quite nice). The pellets were brought inside, dissected, and examined under the microscope (see Figures 1 and 2).

The magnified image showed what appeared to be a partially masticated (chewed) piece of fiber, probably grass. This is where I was informed about the double eating called cecotrophy. My student hypothesized that this sample might be something that had not been fully digested and the rabbit would come back and eat it another time.

The Scientific Process

I really like the scientific process that went into this project, even though I’m not sure I agree with the final hypothesis. The project started with background research that yielded a plan for field observation. The field observation resulted in samples being collected and returned to the lab for analysis. The analysis produced some interesting, enigmatic results, which lead to a proposed hypothesis that integrated the observations based on the original background research.

The only things I would like to add to this type of IRP is to have students include a detailed scientific sketch, much like the sketches of the early botanists and naturalists. I really like how these drawings integrate acute observation and artistic interpretation.

Insects with solar cells

Insect_in_Lindos_Rhodes — The yellow stripe on the oriental hornet's abdomen may act as a solar cell. (Photo by MattiPaavola via Wikimedia Commons).

We’ve seen that autotrophs get their energy from sunlight or chemical reactions, while heterotrophs get their energy from eating other organisms. We’ve also seen that some protists, called mixotrophs, can do both.

We have not yet discussed reptiles, which are heterotrophs (as are all members of the Domain Animalia), but use the sun to regulate their internal temperature (they’re ectotherms).

According to a recent article, the yellow pigment on the oriental hornet’s belly can convert sunlight to electricity, and is believed to have some role in photosynthesis in some plants.

The researchers used the pigment to make their own solar cell, but it proved to be quite inefficient, only converting 0.335% of the incoming light to electricity. However, the microscopic ridges on the hornet, and the layering of the insect’s cuticle, suggest that the hornet itself is more efficient.

I’m not quite sure how the hornets would use the electricity if that’s what they’re doing, but they are more active in sunlight than in the dark, so some type of “solar harvesting” is probably going on.

The Princess Bride is even better with lightsabers

We’ve yet to work on swordfighting scenes for our Dinner and a Show performance, but wouldn’t it be neat if we could use lightsabers!

How to disagree

Graham's_Hierarchy_of_Disagreement — Paul Graham's Hierarchy of Disagreement (image adapted from Wikipedia).

Faced with the rapidity at which anonymous conversations on the internet deteriorate, Paul Graham’s broken things down into six levels of argument. It starts with name-calling at the bottom and ends with the Refutation of the Central Point at the top.

This is a wonderful model. I especially like the diagram because it’s really easy to pick out which level your argument is on. I’m going to make a poster sized version of this and post it on the wall. And, there’ll be a lesson.

Facing Facebook

Rheingold’s social-media class did an exercise that changed the way many of his students interact with Facebook.

Each student projected their profile on a screen with everything but their name or picture. Everyone had to guess whose profile was on display. Estela Marie Go, an undergraduate student in the class, says she suddenly realized that she didn’t like the way Facebook forced her to define herself with a list of interests.
—Sydell (2010) on NPR.

A number of my students have Facebook accounts. I have one too, but I think I’ve used it twice in the year that I’ve had it. Part of my problem is about how it accelerates the loss of privacy inherent to living on the net. However, I also have a very big problem with its insular nature, the fact that it is its own walled-off section of the internet. The two times I’ve used it have been when people I knew from inside the wall wanted to share something and I could not get to it from outside. I also find it difficult to give so much personal information, about my history and my habits to a single company.

So I’m always enthused to see other people coming to the same conclusions, like those in NPR’s recently broadcast story about how, “New Networks Target Discomfort With Facebook.”

Perusing Wikileaks’ Cables

Wikileaks’ recent leak of U.S. State Department cables offers the student with a politics/geography interest an amazing glance into the role of U.S. diplomats. There are however, a lot of cables.

The Atlantic magazine has come up with an interesting way of perusing the information. Their Cablegate Roulette webpage puts up a random cable every time you press the “Load a new story” button.

What’s also nice is that they provide a sentence or two that gives the context of the cable so you don’t have to puzzle it out on your own.

The cable excerpts are brief, well written and quite informative about the political goings-on in different parts of the world. They could make an interesting supplement to the geography curriculum. The self-motivated student with a geography interest would find these quite fascinating because you have to have a basic knowledge of the world and recent history to understand what’s going on.

An example:

An executive with Kazakhstan’s national gas company has dinner with the U.S. ambassador at the Radisson hotel in Astana, the capital of Kazakhstan.

FROM: ASTANA, KAZAKHSTAN
TO: STATE DEPARTMENT
DATE: JANUARY 10, 2010
CLASSIFICATION: SECRET
SEE FULL CABLE

¶7. (S) The Ambassador asked if the corruption and infighting are worse now than before. Idenov paused, thought, and then replied, “No, not really. It’s business as usual.” Idenov brushed off a question if the current maneuverings are part of a succession struggle. “Of course not. It’s too early for that. As it’s always been, it’s about big money. Capitalism — you call it market economy — means huge money. Listen, almost everyone at the top is confused. They’re confused by their Soviet mentality. They’re confused by the corrupt excesses of capitalism. ‘If Goldman Sachs executives can make $50 million a year and then run America’s economy in Washington, what’s so different about what we do?’ they ask.”