Walking
into class today we were immediately greeted with the smell of dead fish. Well,
those of us here on time. A few of us were late and we ended up having to do 18
push-ups! Mr. Cawley wasn’t kidding about those, but I feel stronger already.
Once we got our workout in for the day and sang the Bahamian National Anthem we
were re-assigned seats and told we would be dissecting a shark. Given gloves
and aprons and a dogfish shark, we were split into teams of 4 and told to dig
in - literally. At first everyone was a little hesitant, but after the first
incision was made we dove right in.
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| singing the Bahamian national anthem! |
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| Examining the shark! |
We learned about the fins: the dorsal, pectoral, and pelvic fins. After cutting our poor little shark open we were overwhelmed by a gigantic liver. We later learned in a documentary that this liver not only filters, but also works as a swimming bladder and keeps the shark buoyant. Then we identified the pancreas, spleen, rectal gland, spiral intestine, and gallbladder. Ms. Swain even took one shark and showed us its brain! It was awesome. Since sharks have cartilage rather than bone, it wasn’t too hard for us to open the cavity to the brain. We admired the heart and mouth as well as the “teeth” on its skin. Some people cut out every organ in the shark and others kept theirs intact, but all of us enjoyed it (well almost all of us, sorry Spencer). After affectionately naming my shark Carol, it was sad to see her go but Mr. Cawley assured us that the sharks would be back tomorrow for our practical anatomy test!
Mr. Cawley wasn’t done yet with his fishy plans. After we dealt with the shark, we were then given a slimy surprise! A squid.
The squid was very interesting to dissect. First, we found a bird-like beak that attached to the bucal muscle (similar to an esophagus), then we found something that looked like a clear plastic straw called a Pen. It felt like it was made of plastic and stabilizes the squid’s body. We learned that squids used their two long tentacles to grab a fish, spongebob, or some other unfortunate creature, pulled them in and trapped them with their 8 short arms where they face death to the squid’s beak. After further examination, we learned that the squid used jet propulsion to move. It sucks in water from the top of its mantle and forced it out through its syphon.
The squids also have gills, similar to a shark, but theirs are inside of their body and look like feathers. The squid’s brain is also extremely small -- only one group could find it! In addition, we found the squid’s ink sac which is what they use to scare away predators. We even used the ink from there to draw with the Pen!
After two dissections, it was the perfect time for lunch (not) . Coming back we ended up having to do even more pushups! Well at least we’ll all be in shape for the trip. We were informed that we would be watching two documentaries on the dissections of the giant versions of what we dissected earlier: the Great White Shark and Giant Squid.
Beginning with the Great White, we learned how misunderstood sharks have been since the movie Jaws came out. More people die by toaster oven then by sharks every year, and most people in a shark attack are only bitten with a taster bite then the shark realizes it doesn’t want to eat a person. Seeing experts do similar to what we did was super cool. They explained to us what the organs and muscles we saw earlier did for the shark. We learned how their teeth aren’t attached to their jaw and they continue to grow and lose teeth. Also, it is very hard to know the evolution of sharks since cartilage doesn’t fossilize, only the teeth do. Sharks are essential to the marine ecosystem. Even though I don’t want to see a Great White in the Bahamas, I have a new appreciation for sharks. However, seeing a Nurse Shark would be pretty cool (its Ms. Swain’s spirit animal)!
The second documentary revealed that the giant squid live in the deep sea and are rarely seen as a result. Giant squid rely on stealth instead of speed to catch their prey. The dissection of the giant squid was almost the same as the dissections carried out right before lunch except, well, its GIANT. Its eyes were as large as a baseball!
We learned that squid, along with other members of mollusca, are capable of changing their color to blend in with their surroundings. Some can even glow! The dissection video showed the squid’s bioluminescence organ. They have got to be aliens! The scariest thing is that this giant squid isn’t even close to the size of the colossal squid. The documentary featured a colossal squid being captured near antarctica. Yea, its big.
It was a very eventful day in the marine science class and it got everyone even more excited for the Bahamas, as if that was even possible. Well that’s it for today! 7 more days until we leave (not that we’re counting or anything).
Talk to you later,
Ally and David
