WASHINGTON — It felt like a hard-boiled egg to 17-year-old Anna Rediger and looked a bit like cauliflower. But in her gloved hand was a piece of a sheep's brain, which she had scraped, sliced and probed to learn how the organ--and, by extension, a human brain--is designed.
The senior at Oakton High School in Fairfax County, Va., was performing a dissection, one of several teacher Ann Starr's anatomy and physiology class will do this year to study the systems--respiratory, digestive, etc.--that make up living things. Earlier in the year, a fetal pig and a chicken were dissected; coming up are a cat and an animal heart.
"It's kind of amazing to realize that this is, well, real," Rediger said. "You really do learn better this way."
Dissections have been a staple of classroom science since the 1920s. But things have changed.
Once the province of high school, dissections have moved into earlier grades, science teachers say. It's common for middle school students and some elementary classes too.
"It works if it fits their curriculum, although I don't necessarily encourage it," said Odette Scovel, science supervisor for Loudoun County, Va., Public Schools. "The skill of the teacher plays a big role in the decision."
A 2002 poll by the Humane Society of the United States showed that a majority of biology teachers say they believe the real thing is a better educational experience than a computer-based virtual alternative. The National Association of Biology Teachers supports the practice of dissection when done for legitimate educational purposes, as does the National Science Teachers Association.
"I would use the example of driving a real car versus a driving simulation on a computer or in a game room machine. The real-time dissection provides awareness to all of the senses--touch especially--texture, form, etc.," Kenneth Roy, chairman of the Science Safety Advisory Board of the science teachers association, wrote in an e-mail.
Across the country, more dissections are performed than ever before, according to its advocates and critics. The non-profit Humane Society estimates that about 6 million vertebrate animals are dissected in U.S. high schools alone; the number of dissections of invertebrate animals is probably comparable.
Meanwhile, dozens of kinds of animals are used today, selected to teach different lessons. While frogs remain the most commonly dissected animal, others include dogfish sharks, rats, mice, turtles and snakes, and invertebrates including starfish, earthworms and grasshoppers.
The rise of the animal rights movement has sparked an increase in opposition to the practice, accompanied by a movement to allow students who don't want to participate to be given alternative educational options, said Kathleen Conlee, director of program management for animal research issues at the Humane Society.
Nine states have passed laws requiring schools to grant students alternatives to dissection; four have informal policies that demand the same thing.
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For some students, a computer version
For students who are squeamish or morally opposed to dissections, there is an alternative: computer-based virtual dissections, sometimes with three-dimensional technology that enhances the vividness of the experience.
Some students prefer the computer versions because they are "tuned in electronically," said Odette Scovel, science supervisor for Loudoun County, Va., schools. "That is their method of learning, and they can translate a virtual environment very easily into a real environment."