Tuesday, August 17, 2004

Diversity labs

I'm starting up a new course this fall, and it's finally time to make all the nitty-gritty decisions about exactly which labs get run and when, and what will occur in each lab.

It's one thing to say, "I want to have a lab that introduces the kingdoms (or protists, or plants)," and it's quite another to actually find said lab. Most of the labs I've seen haven't been ideal. Many read like a mediocre textbook and are simply glorified lists of facts about each group of organisms within the lab's chosen taxon. The only student work in these labs is usually to sketch a given set of organisms (usually on slides or in biomounts), label their sketches or pre-prepared sketches, and in the process learn a large number of anatomical terms and life cycle details about the organisms they're "observing".

While students can benefit from sketching organisms and reading selected details about the group of organisms they're exploring, these labs require no critical thinking, and are usually dreadfully boring. Most of the lab manuals I've looked through have at least seven or eight labs built in this style as they march through the lineages of all the kingdoms.

What I'd like to see more of in these labs are components that require critical thinking and active exploration on the part of the student. Instead of simply listing the characteristics that differentiate the taxa, why not show students the organisms in each taxa and have them try to figure out what differentiates them? Even if the students flounder and don't come up with the ideal characteristics, they'll have spent an hour or more critically examining the organisms in the lab room, and it should be easy for an instructor to lead an end-of-lab discussion on what the actual defining characteristics of the group are, including some relevant anatomy and life history lessons.

Thinking along these lines I've been working on designing the first lab of the semester. My primary goal is to introduce some basic information about the currently accepted domains and kingdoms, preparing the students to explore each kingdom in more detail later in the semester. Secondary goals are to introduce the ideas of taxonomic classification, expose the students to organisms they may not have seen before, and have an interactive lab where the students get to move around and meet their peers.

I've come up with a few basic ideas that could work for the lab. The first assumes the students do not know what all the kingdoms of life are (not a bad assumption, in my experience), and the remainder assume the students have had some recent introduction to the topic.

1) Randomly position organisms representing each kingdom around the room, without any labels other than a species name or a number. The primary task during lab for students would be to group the organisms into kingdoms, and in doing so determine what makes the kingdoms different from each other. Probably the easiest way to run the lab would be to have groups of students quickly sketch each organism onto a card, and then sort the cards into groups on their lab tables.

2) Place organisms from each kingdom on a separate table (e.g. table 1 is animals, table 2 is plants, etc.). The students' primary task during lab would be to determine the similarities between all the organisms within one kingdom (table), and then determine what differentiates each kingdom from the other kingdoms.

3) This starts out the same as number two (each kingdom is on a different lab table), but instead of labeling each table with the kingdom name, the tables are left unidentified and it's up to students to first figure out which kingdom is at their table, before continuing with the rest of the lab as described above. For some tables it will be obvious (*cough*animals and plants*cough*), but for others it could be a challenge.

4) Distribute organisms from the different kingdoms randomly around the room, but since students have been introduced to the kingdoms already, their task would be to determine which kingdom each organism belongs to. This could be done either by giving the students keys and having them key out each organism, or by having them try to determine the answer based on material that has been introduced previously (e.g. basic characteristics of each kingdom as discussed in lecture). My preference would probably be the latter, since using keys can get very mechanical, though exposure to keys is important.

All of these options would end with a class discussion wherein the actual characteristics of the kingdoms would be introduced, along with some of the basic biology of each kingdom.

The main problem with the first option is that it requires that the students not come in with recent knowledge about the kingdoms. Since I have lecture before lab I will almost certainly be lecturing about the domains of life then, and preventing myself from talking about the kingdoms in that lecture would be awkward.

For now I'm leaning to the third option (kingdoms divided by table, but left unidentified initially), possibly including some unidentified organisms on the side of the room so students can test the effectiveness of their chosen characters.

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