First we dissected an earthworm. We had to cut the earthworm in half but mckenna and i obviously messed it up so we did broke some organs. Next we pinned down the sides. Our earthworm was 23 centimeters long with 37 segments. We examined the anterior/mouth, the sperm ducts, the genetal setae, and the clitellum. When looking at the circulatory system, we saw the aortic arches, the dorsal blood vessel, and the ventral blood vessel. An earthworm has a closed circulatory system. After examining all of the organ systems, we looked for the brain. It was tiny near the anterior. Although simple, the earthworm was interesting to dissect.
The second dissection was on a clam. We examined the outside of the clam and were able to see the concentric lines which show each individual clams' growth. First we had to pry open the shell of the clam. This was the most difficult part. Once we got it open, we identified the mantle and the foot. The mantle is what protects the clam and the foot is what allows the clam to move. We also examined the digestive system. An interesting part of the clam dissection was observing the umbo. The umbo is the upper hump near the hinge of the shell. It is the oldest part of the clam. I also learned the difference between clams and mussels. Clams burrow in the sand/mud while mussels attach themselves to rocks and other surfaces.
The third dissection was on a squid. This was the most interesting for me because it was the largest. The squid has 8 arms and 2 tentacles. Before beginning the dissection, we examined the mantle, the fins, the water jet, the eyes, the tentacles, the arms, and the sucker discs. Once we cut open the squid, we examined the stomach, the ink sac, the esophagus, the gills, the heart, the gonads, the anus, and the pen. I also enjoyed using the ink sac to write my name. The eyes were interesting too because they were a purple metallic color. Our squid was a male and we examined his white gonad. The squid has 2 gills which are feathery structures. After finishing the dissection, I found the brain. It was small and a yellowish color. I really hate doing dissections. Most people find them really interesting but I think it is very gross.