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Why Do Students Dissect Frogs?

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There are many surgeons who say that they first discovered their life’s passion standing over a dissected frog in a middle or high school biology class. But, apart from inspiring the medical professionals of tomorrow, what is the purpose of dissection? And more importantly, why is everyone always dissecting those poor green amphibians?

There are many reasons that students in biology classes are asked to perform dissections, and they have a lot to do with understanding the body and the wider world. In dissecting an animal, students see, touch, and explore the various organs in the body. Seeing these organs and understanding how they work within a single animal allows students to understand how these systems work within many other animals, including themselves. While there are various aspects that may differ between humans and other animals, many of the organ systems in complex animals work in similar ways to those of humans.

One reason frogs are often chosen to be dissected is that their bodies provide a good overview of the organ systems of a complex living thing. While the way their bodies work is nowhere near identical to a human’s, there are many similarities. The organs present in a frog, and the way they are laid out in the body, are similar enough to humans to provide insight for students about how their bodies work.

In addition to learning about themselves, students can learn about ecology and evolution through frog dissection. Certain body structures and adaptations can be seen in frogs that illustrate how they evolved over time and how they fill particular niches in the ecosystems they belong to. For example, the tongue of a frog has adapted to have great length, strength, and speed in order to effectively catch insects in flight. The role that this tongue allows the frog to fulfill—consuming insects as its primary food source—is important in the balance of many ecosystems the frog is a part of.

There are practical advantages in using frogs, too. They're an appropriate size for dissection in the classroom and make the process manageable for students and teachers. Also, frogs have a relatively short life span to begin with, and while some species are rare in some places, others are abundant and are therefore prime candidates for use in dissection. Bullfrogs, for example, are an invasive species in much of the United States. While they naturally help to control insect populations, they are also threatening native populations of other animals. This is especially the case when it comes to other frogs—bullfrogs are known to eat other frogs and drive other frog species out of their natural habitats. Bullfrogs, while not the only frogs used for dissection, are among the most common. The use of these frogs serves a dual purpose, controlling their populations and providing a learning experience at the same time.

While it is true that many people, for many different reasons, oppose dissection in the classroom, and offer alternatives like models or online options, dissection is still a valued educational tool thanks to its hands-on nature. It is thought that if students see and feel these organ systems for themselves, they will take more out of the lesson than if the teacher just lectured or assigned readings about it. Also, some teachers express the hope that by learning about their own bodies through dissection, students will come to respect how their bodies work, and think about how they treat them and what they put into them.

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Animals
Owning a Dog May Add Years to Your Life, Study Shows
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We've said that having a furry friend can reduce depression, promote better sleep, and encourage more exercise. Now, research has indicated that caring for a canine might actually extend your lifespan.

Previous studies have shown that dog owners have an innate sense of comfort and increased well-being. A new paper published in Scientific Reports and conducted by Uppsala University in Sweden looked at the health records of 3.4 million of the country's residents. These records typically include personal data like marital status and whether the individual owns a pet. Researchers got additional insight from a national dog registry providing ownership information. According to the study, those with a dog for a housemate were less likely to die from cardiovascular disease or any other cause during the study's 12-year duration.

The study included adults 40 to 80 years old, with a mean age of 57. Researchers found that dogs were a positive predictor in health, particularly among singles. Those who had one were 33 percent less likely to die early than those who did not. Authors didn't conclude the exact reason behind the correlation: It could be active people are more likely to own dogs, that dogs promoted more activity, or that psychological factors like lowered incidences of depression might bolster overall well-being. Either way, having a pooch in your life could mean living a longer one.

[h/t Bloomberg]

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Big Questions
Why Don't We Eat Turkey Tails?
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Turkey sandwiches. Turkey soup. Roasted turkey. This year, Americans will consume roughly 245 million birds, with 46 million being prepared and presented on Thanksgiving. What we don’t eat will be repurposed into leftovers.

But there’s one part of the turkey that virtually no family will have on their table: the tail.

Despite our country’s obsession with fattening, dissecting, and searing turkeys, we almost inevitably pass up the fat-infused rear portion. According to Michael Carolan, professor of sociology and associate dean for research at the College for Liberal Arts at Colorado State University, that may have something to do with how Americans have traditionally perceived turkeys. Consumption was rare prior to World War II. When the birds were readily available, there was no demand for the tail because it had never been offered in the first place.

"Tails did and do not fit into what has become our culinary fascination with white meat," Carolan tells Mental Floss. "But also from a marketing [and] processor standpoint, if the consumer was just going to throw the tail away, or will not miss it if it was omitted, [suppliers] saw an opportunity to make additional money."

Indeed, the fact that Americans didn't have a taste for tail didn't prevent the poultry industry from moving on. Tails were being routed to Pacific Island consumers in the 1950s. Rich in protein and fat—a turkey tail is really a gland that produces oil used for grooming—suppliers were able to make use of the unwanted portion. And once consumers were exposed to it, they couldn't get enough.

“By 2007,” according to Carolan, “the average Samoan was consuming more than 44 pounds of turkey tails every year.” Perhaps not coincidentally, Samoans also have alarmingly high obesity rates of 75 percent. In an effort to stave off contributing factors, importing tails to the Islands was banned from 2007 until 2013, when it was argued that doing so violated World Trade Organization rules.

With tradition going hand-in-hand with commerce, poultry suppliers don’t really have a reason to try and change domestic consumer appetites for the tails. In preparing his research into the missing treat, Carolan says he had to search high and low before finally finding a source of tails at a Whole Foods that was about to discard them. "[You] can't expect the food to be accepted if people can't even find the piece!"

Unless the meat industry mounts a major campaign to shift American tastes, Thanksgiving will once again be filled with turkeys missing one of their juicier body parts.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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