This week the high school students dissected two dogfish sharks. These are pretty cool to dissect. They are fairly large, over 50 cm long from head to tail. You can see in the photo, I placed 3 dissection mats on an old cookie sheet that I use for science experiments.I found a nice handout online that had lots of questions, some of which we had to look up on the internet – new vocabulary words, finding certain organs and details on the shark and even taking measurements.
One of the first things students do is feel the shark skin. Its nice and smooth if you ‘pet’ it from head to tail, but if you rub your hand in the other direction is feels very rough. This is because the skin is covered with little scales. We took a sample of the skin and put it under the microscope (40x), you can see the sharp scales below.
I watched the following videos, posted by South Dakota Public Broadcasting, before class so I would have some idea what we were looking at.
There’s a link below the videos on youtube to other dissection videos and lesson plans/checklists for dissection. Unfortunately the dogfish shark resources have been uploaded yet but they should be up by the end of the summer (2019). While watching the videos I saw they found fish skulls in the stomach so I made sure to have my students open up the stomach and they found brine shrimp in one of them! We took the head of one of them and put it under the microscope to look at brine shrimp’s compound eye.
The teeth are also very interesting to look at. I had two sharks from two different companies and I have to say the dissection specimens from Carolina.com are always the best.