Rabbit Dissection

Yesterday, Dr. Sansone was kind enough to lead my Biology class through a small mammal dissection (details here). He’d brought in five New Zealand White rabbits (2 male and 3 female) that had been raised for market by an Amish family in northern Missouri.

Over our two-hour class period, we had time to examine the organs in the abdominal and thoracic cavities in some detail. Students had been prepared with group reading assignments of the different organ systems based on the anatomy outline.

Dr. Sansone points out a rabbit's ovaries. A kidney is visible to the lower right. — Dr. Sansone points out a rabbit’s ovaries. A kidney is visible to the lower right.

After the dissection we removed the pelts and froze them for later preservation. We also froze the carcases for later. I’ve convinced Mr. E. that cooking them would be a great interim activity. Mr. E. is a bit of an epicure, so it did not take much convincing.

Notes

Only one student declined to participate in the dissection for ethical reasons. About half of the class declined to observe the harvesting. Four students volunteered to assist in the harvesting, two of whom were not even in my biology class. They were seniors. One of them, P., had done it before and demonstrated the procedure for us.

An Outline for Anatomy

Concept map for the study of anatomy. This diagram will be used for the introductory lesson.

Because we have the opportunity to get a few rabbits, we’re starting Biology this year with anatomy. In the first week, our discussions will be based around the rabbit dissection so we’ll be focusing on the systems where the organs are easiest to find: the fluid regulation/excretory, respiratory, cardiovascular, reproductive, and digestive systems.

Preparing for Rabbit Dissection

References

Linn (2000) has a good overview of general rabbit biology and the internal organs in Rabbits: Biology (pdf).

For lots of detail on how to dissect a rabbit try Bensley’s Practical Anatomy of the Rabbit (free on Google Books)

AnimalLearn.org has a good list of free and for fee online dissections of various organisms. No rabbits as of this moment though.

Teaching Organic Farming

One of these days I’d like to put in a garden at school. Or maybe a few gardens. An indoor hydroponic system would be nice for the winter months, as would a greenhouse. However, the easiest thing to start with might be putting in some raised beds. To this end, the University of Santa Cruz’s Center for Agroecology and Sustainable Food Systems has detailed information in their Teaching Organic Farming & Gardening: Resources for Instructors manual.

↬ Mr. Sansone.

Understanding the Extinction of the Dinosaurs (and the Survival of Mammals)

This neat paper (Robertson et al., 2013) in the Journal of Geophysical Research makes an interesting attempt to explain the pattern of extinctions that occurred at the end of the Cretaceous: why most of the dinosaurs died out, and why ocean organisms were more severely affected than freshwater organisms by the long winter after the asteroid impact.

The flow chart explains:

Diagram of contrasts between freshwater and marine environments for factors potentially causing extinction in aquatic environments after the Chicxulub impact. (Image and caption from Robertson et al., 2013).

They also include an interesting figure showing how long an organism might survive based on how large it is, which I may be able to use in pre-Calculus when we’re discussing log scales and linearizing equations.

Allometric relationship between body size and time to death by starvation for multicellular poikilotherms in the absence of food (red, drawn from the equation of Peters [1983, p. 42]). Names of various types of organisms are shown as an indication of body size. Image and caption from Robertson et al., 2013. — Allometric relationship between body size and time to death by starvation for multicellular poikilotherms in the absence of food (red, drawn from the equation of Peters [1983, p. 42]). Names of various types of organisms are shown as an indication of body size. (Image and caption from Robertson et al., 2013.)

The article is written well enough that an interested high school biology student should be able to decipher (and present) it.

Crayfish: Charismatic Mesofauna

This year, the creek is teeming with crayfish, especially compared to last year during the drought when the creek dried up and the crustaceans were hard to find. I had five students out collecting organisms on Wednesday, and they came back with ten crayfish ranging in size from a couple centimeters long, to one that was about 12 centimeters from claws to tail.

Crayfish in a jar. Seen through stereoscope. Magnification unknown.

I was just looking at one of the pictures I took and realized that I did not know what species it belonged to. I’ll be having students do reports on individual species for biology next year, and I’d be very surprised if someone did not choose crayfish. They’re so many of them and, as my students from Wednesday will attest, they’re just so charismatic. While I’ve not looked into it much myself, the Crayfish & Lobster Taxonomy Browser seems a decent place to start researching.

A Tadpole with Legs

Among the interesting things we collected from the creek yesterday, was a tadpole that was in the process of developing legs.

This is particularly interesting since we’ve had a tadpole in our fish tank since last fall that still has not shown signs of transforming.

Constructing a Wooden Slide Tray

To have somewhere to store the slides I’ve been making, I needed a slide storage box. They’re pretty cheap, but they’re also pretty simple to put together with stuff I could, mostly, find around the house: some scrap wood (from an small wooden CD holder tray that I’m not using any more); a small sheet of clear acrylic (from the hardware store); a short piece of sticky-backed, rubber foam for insulating windows (to keep the slides pressed into place so they don’t move in the box); and some craft glue (ModPodge). For tools, all I used were a few clamps and the saw on a pocket tool.

Using the pocket saw was the biggest pain because I had to cut little slots into the wooden frame to hold the slides. Twenty five slides meant 50 slots, and although the wood was soft, the width of the blade was almost exactly the width of a slide, so if the slot was not perfectly vertical the slides would not fit properly and I’d have to carefully saw it a little bigger. The clamps were a big help with the sawing.

The base of the slide tray was put together with scrap wood and the saw on the pocket tool.