Slicing into science

The smell of formaldehyde permeated the halls of Sidney Middle School this week as seventh grade students learned about vertebrate anatomy in their life science class by dissecting frogs.

"It's kind of nasty, but fun," Lainey Hausmann, 13, said as she and her lab partner, 13-year-old Karly Sylvester, exposed the brain of their dissected frog.

Seventh grade science teacher Joydene McCarville said the experiment is done annually in the seventh grade life science class. This year, she had five classes dissecting close to 60 preserved frogs in teams of two to three students.

"It depends on the number of kids I have in a class," she said.

McCarville said by studying the dissected frogs at a cellular and tissue level, the students come away with a better understanding of what their own system do, and have a better appreciation of how those systems affect them in everyday life.

"The systems that we have as humans, they can study them on this level," she said. "When they cut a (frog) tendon, they understand why they need to stretch for track. It's so they don't injure themselves. We can get a closer look at it."

Students in the class began with a living experiment where they studied crawfish.

"But we don't dissect them," McCarville said. "Because they have to have a appreciation for life before we start taking life apart."

Earlier this year, the students dissected earthworms, which McCarville said gave students a sense of an organized set of systems.

"They learned how food moves through the digestive system and how that is absorbed into the blood stream," she said. "So that when we study human systems, it makes a big difference. They have had that experience, and can apply (what they learned) to their body."

Sylvester said she preferred the frog dissection to the earthworm.

"That was grosser," she said.

With the frog dissection, McCarville said the students go from an invertebrate, or animals that do not possess a backbone, to a vertebrate.

"Which, again, is more like them," she said.

As part of the frog dissection, students studied the animal both outside and inside, looking at the different organs system and learning how they function.

For example, McCarville said the students inflated their frog's lungs during the experiment, which she said demonstrated how smoking can harden the lungs.

"Because they saw frogs that were not necessarily healthy," she said. "If you can't inflate a lung, and you can't get oxygen in, then you can't get oxygen into the bloodstream. Therefore, it can't get into the cells and produce the energy it needs to do all the things it needs to do.

"Then they understand, and I don't have to preach to them about not smoking. It's right there in front of them."

While some students feel at the start the experiment is outside of their comfort zone, McCarville said most find once they started dissecting that is is not as big a deal as they convinced themself it would be.

"They find that they're stronger than they thought they were," she said. "There are some that this is right up their alley. They love it."

McCarville said given the option, her students prefer the live dissection compared to a virtual one through a computer.

"Most of them say that they learn so much more this way," she said. "On the computer, it's click and drag, and just not the same thing.

"When you're holding that lung, and it's soft, you feel it and you understand when it inflates. It's not like reading about it. They get the real experience."

For the rest of the semester, McCarville said the students are done with dissection, and will be moving on to learn about higher vertebrates such as birds and mammals, before ultimately tackling the human body system and genetics.