In 7th grade science, we have just finished a unit on
Sponges, Cnidarians, Worms and Mollusks.
We looked at worms and most of the students thought of worms as slimy, squiggly creatures. And in fact, many are. There are, however, many kinds of worms that look nothing like the worms that are used to bait fishing hooks.
Click Here For Pictures
Worms are classified into three phyla: Platyhelminthes or flatworms, Nematoda or roundworms, and Annelida or segmented worms.
For each phylum, we discussed the characteristics, life style, reproduction, and if that worm caused diseases or not. The students also looked at laser disks that contained pictures of examples of each phylum. We also discussed some of the worms that are parasites and use humans as an opportunistic host.
We believe one of the most important ideas we discussed was symmetry and the various types of symmetry: bilateral, radial, and asymmetry. Using these definitions of the three types, the students then had to identify the type of symmetry when looking at organisms.
During this unit we also had a dissection lab and we dissected earthworms. The students loved it, and they identified the different internal and external parts of the worm. (They also wanted to wear gloves and not touch it with their bare hands!)
Here are some links that help with dissection and even go into the parisitology of various worms.
Click here for COOL WORM site!!!
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