SCIENCE LAB - This isn't Dinner at Phillip's Seafood Restaurant!

Alex T. and Gabby C. dissecting a squid.

Seventh-grade Science has been full of fascinating topics, all relating to the diversity of life.  Right now we are studying Invertebrates, animals without backbones.  One of the most interesting facts we have learned about Invertebrates is that only 2% of all animals in the Animal Kingdom have a backbone, where 98% do not.  There are so many invertebrates to study, but due to our limited amount time, we have focused on four major groups.  These groups include Cnidarians (ni - dare’- ee - uns), Mollusks, Worms, and Arthropods.  These four groups show a wide range of body forms and lifestyles that we can explore in our labs.

Brianna T. dissecting a clam.

Cnidarians are invertebrates that have two body forms.  They can be a polyp or a medusa.  Both forms have a sac-like body with one opening surrounded by tentacles.  The most common Cnidarians are jellyfish and coral.  In our lab, we observed a type of Cnidarian called Hydra.  It has a polyp body form.  We looked at it under a microscope and watched its movement.  At the end of this lab, we were able to feed the Hydra a shrimp and watch it digest the food.  This part of the lab was the most fascinating, because we were able to watch how the Hydra detected the food with its tentacles and forced it into its food grove.  Once the food got into the Hydra’s body, its longitudinal muscles contracted and helped digest the shrimp.  Once we completed all the lab activities, we recorded our observations in our lab manual.

This is the squid we dissected.

Another type of invertebrate that we studied was mollusks. There are about 50,000 different species of mollusks.  The most familiar mollusks include snails, clams, slugs, oysters, squid, and octopuses.  We studied two species in this group, the clam and the squid.  Both are very different in their body and design.  We first had a discussion on how the animals’ structural features help them survive.  Then we completed labs, where we dissected a clam and a squid to see their features.  To dissect the clam, the first thing we did was open the shell.  We looked at the clam’s body and labeled its various parts in our lab manual.  When we were done, we put the clam away and got a squid.  For the squid, we also dissected it.  We had taken out the mantle, eyeball, beak, and ink sack.  We sketched the squid in our lab manual and labeled its parts.  One of the most fun things for the students to do was write with the squid’s ink.

 Here are some students’ comments:

“I loved doing it.  I thought it was really interesting.  I especially liked writing with squid ink.  The squid also had lots of cool parts like the tentacles and mouth.” –Emma B.

“It was really gross but also interesting to see the parts of the squid.” –Hallie A. 

-- Text and Photos by Jackie M. (Class of 2016)

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