Reflections on mitosis images

For years the Bio 10 team has used a University of Arizona interactive website to review the phases of mitosis. In addition to specific information about each of the phases, this site is excellent, because it gives the students some small images and has them select the phase each image represents. If the students select incorrectly, a short description helps them understand their mistake.

It is good to review these tested and true sites. The last thing on the worksheet was a video of a cell actually undergoing mitosis. The animation site was dead, so used YouTube search to find a mitosis animation that worked equally well, and give it to the students with the worksheet.

The next thing was to put what they learned together with previous microscope skills they learned last semester. The team decided to have the students do size calculations of the images they saw on prepared slides. Once students had demonstrated this skill at two different powers of magnification, I felt the same task for the other four phases would not improve student learning much, so I modified the lesson to have the students evaluate images from the Internet and label these larger images, which offered more opportunities for detail.

First I had them work with the microscope and find onion root tip slides in anaphase. I chose this phase because students would find many of the other phases and would identify them before they found a much rarer anaphase image. Then:
"Using images from your computer, find plant cells in each of the following phases: INTERPHASE, PROPHASE, METAPHASE, and TELOPHASE. For each phase, look at three different images and choose one that you feel best represents that phase and make a detailed, labeled diagram of it in the appropriate boxes. Include the URL of the site at the bottom of each box."
Flickr image courtesy of The JCB.

Many of the prepared slides were old and their colorizing stains had faded, so the use of Internet slide images was timely. I briefly reviewed with the students how to use Google images and reminded them of the importance of giving references in their presentations.

I had reviewed the images of mitosis on Creative Commons and found only two that were relevant, not enough to create a lesson around. One was the image above. The other was an attractive painting to the left that actually looked like a phase of mitosis.

Flickr image courtesy of rakka.

I verbally told students to check if there were any errors in the images they chose. Looking back on that now, there is little chance they would have seen errors, because the images would more than likely not include labels. A better statement would have been to either check if the phase was correctly labeled or check labeled diagrams (not slide images) of the various phases to see if structures were mis-labeled. An obvious mistake online would have been labeling a centriole on a plant cell. (With the exception of mosses and ferns, plant cells do not have centrioles.)

The use of online images was a good idea. The clarity of detail of the images online allowed students to label their work more thoroughly. The major learning that I didn't expect in this lesson came from how students documented their references. There were four areas I reviewed with students after grading their work:

1) With URLs that are long, students didn't know how to break them up, so they tried to squeeze them into one line. I explained they can move to the next line after any hash mark.
2) Google uses dots, "...." in URLs that are long. Some students copied these: "www.microscopy-uk.org.uk/.../jronionroot.html" and needed to be shown that the URL is in the address line for the browser .
3)Students sometimes gave only the address of the server location, only up to the first hash. We discussed how this is a parent address for all the files in the folders on the server. I explained all valid URLs should end with something like .html, .gif, or .jpg.
4)Students continue to use "http://images.google.co.th/...." as the URL for sites. I explained how Google is a search engine and showed them where the URL is embedded in this address and suggested the image they studied would be better if they actually clicked on the "See full sized image" button.

This lesson brought together a few of the standards we discussed in the course: EL1b, EL1c, EL1d (making diagrams from images and labeling them is considered data processing in Biology and IB Sciences, and EC2b.

I could have expanded this lesson more by having students scan their labeled diagram and display it on a school site for others to view, but I do not believe this would have assisted their learning or the learning of other students. This is a standard I would like to have students do in future activities.