Lesson 7 of Apologia's Exploring Creation with Zoology 2: Swimming Creatures of the Fifth Day is all about "Sharks and Rays," that is, cartilaginous fish. We learned about how cartilaginous fishes are different from bony fishes, including the presence of dermal denticles ("sandpaper" skin).
As with every lesson, we used the curriculum's notebooking journal to aid in our study.
Before we got to sharks, we learned about rays (AKA: batoids). These include stingrays, manta rays, electric rays, and eagle rays. We also talked about sawfish (considered a ray though often mistaken for a shark) and skates.
On Day 2 of this lesson, we got to the sharks. One of the first things we discussed about sharks was their magnificent teeth. We learned that you can measure the length of a shark just by measuring one of its teeth! Every inch of tooth equals 10 feet of shark length; so if a shark tooth is 2 inches long, the tooth came from a shark that was 20 feet long. We decided to put this to the test. We bought a dig kit from Hobby Lobby (we used a 40% off coupon to get it down to $8) that guarantees three real shark teeth per kit. Maggie was so excited!
The teeth are set in this large, shark-tooth shaped rock.
Chiseling away ...
Our three teeth!
This first tooth we found came from a Sand Tiger Shark. (The manual that came with the kit had the information on each tooth.) We measured the tooth and it measured at 0.8 inches, meaning our shark was 8 feet long!
Our second tooth found was from the Crow Shark (now extinct)! WHOA! Maggie was so excited about this because she is obsessed with animals that are extinct or endangered. (Trust me on this. We have every publication that was written in the last 15 years on this subject!) Our tooth specimen is in great shape, with the serrated edges of the tooth still intact. Our tooth measured at 0.8 inches, meaning this shark was about 8 feet long as well!
The last tooth we found was from a species of shark called Otodus obliquus, also extinct. (Maggie was beside herself with excitement by this point.) It measured in at 0.6 inches, meaning this creature was about six feet long. This was such a fun addition to our lesson! We placed our shark teeth in a protective container for our science shelf.
After teeth, we talked about shark senses (including their ampullae of Lorenzini and exceptional sense of smell) and shark pups. We then read Hark! A Shark! All About Sharks by Bonnie Worth ...
... and National Geographic Kids' Sharks by Anne Schreiber.
She then wrote a fact that she learned from each book, which we then placed in our notebook. For the Hark! A Shark! book, she wrote, "that the fastest shark is the mako." From the second reading, she wrote, "that the spined pygmy shark has a glow-in-the-dark belly." Cool.
We then read some publications on sharks that we had in our collections. We read the June 2013 issue of Zoobooks magazine, entitled, "Sharks" ...
... "The Brains Behind the Jaws" article from this June 2008 issue of Smithsonian magazine, about the intelligence of great whites ...
... the "Watching Whale Sharks" article in this February 2015 issue of Highlights magazine ...
... and the "Sharks! Up Close and Personal" issue of Ranger Rick, June/July 2015. (This is a photo of one of the spreads inside.)
We picked up this little Dover book when we visited The Estuarium at the Dauphin Island Sea Lab on Dauphin Island, Alabama, and completed it for her journal. (You can purchase one directly from the Dover website.)
We then investigated each of our Usborne Sharks fact cards, to learn some more fun facts about different shark species.
Mags was especially interested in their extinction risk, listed on each card.
While at Toys 'R' Us to look for a birthday gift for a friend, we spotted this whale shark! Mags had to have her picture with it.
On Day 3 of our lesson, we learned about the different orders of sharks, that is, how sharks are classified. We also learned about two other cartilaginous fish, jawless fish, lampreys and hagfish. These two fish are completely gross, but still fascinating. Maggie then updated her journal with everything she had learned.
It was then time for some sticky fun. We set out to make the "Hagfish Slime" recipe we found in the notebooking journal. (Hagfish eject gallons of slime when startled. Disgusting.) You really only need Metamucil and water for it, so we were ready to go! Here, Mags is measuring 1 teaspoon of the Metamucil into 1 cup of water before the mixture went into the microwave. (We microwaved on high for 4 minutes, let it cool, then repeated twice more until our slime was ready.)
The result was icky but fun!
She had too much fun with this!
Hagfish slime! This stuff keeps in the refrigerator for months! (We won't be keeping ours to find out, though. Yuck.)
After a fun, long lesson, it was time to make our critters for our ocean box. Mags made a hagfish ...
... and asked her Daddy to make this manta ray.
We placed these and some shark stickers into our ocean box. It is looking so good!
Next up? Crustaceans!