Phylum Mollusca

This week we focused on the Phylum Mollusca (click here for my lesson plan)since my dd couldn’t wait to dissect the squid any longer.  I suppose that next week we will go back to cover the worms.

We began by looking through the DK Animal and Ocean books to get a good overview of the phylum.  I believe that the mollusks are second only to arthropods when it comes to number of species.  I wanted to emphasize to my dd how clams, snails, octopus, nautilus, and squid could all be so closely related when they look so different from one another.

On the second day we read through some library books that I found and the best one by far was About Mollusks by Cathryn Sill.  I had my dd fill out the snail anatomy page from Enchanted Learning and then we talked about what we would look for when we dissected our squid and clam.  We also watched several You Tube videos of squid swimming and octopus squirting ink.

Today was the big dissection day.  I have to say that I am thrilled with the quality instruments from Home Science Tools.  I ordered the intermediate package that came with the dissection tools and mat and I also added in a squid (the package comes with 7 other specimes, including the clam).  I do need to order more pins and eventually we will need a larger tray.

The dissection guides are roughly high school level so I decided the night before exactly what I hoped to show dd.  For the clam we identified the muscles that hold the shells closed, the foot, the mantle, and the gills.  For the squid we counted the number of tentacles, examined the suction cups, located the eyes and siphon, found the gills and the ink sack, and determined that our squid was female.  I will add that I am not sure if it is because I had LASIK on my eyes a few years ago or what, but my eyes definitely started getting irritated about halfway through the squid dissection (I never had a problem with this while doing long dissections in college).

Afterwards my dd told me the parts of the clam from a diagram that I had and I am still debating if we should do any narrations.  I think that I may do that tomorrow as a quick wrap-up for our Mollusk week.

I am including a link to a file that contains a clam lab that looks like a lot of fun.  I found this somewhere online and I feel awful that I did not record the link to give the person credit.  We didn’t get around to it because I don’t currently have any brine shrimp.  However, I think that we may do this lab at some point in the next few weeks because it seems really interesting.


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