‘Macfrog’ Allows Virtual Dissection
Like a sheep’s heart preserved in a bottle of formaldehyde, many adults have permanently pickled memories of their high school biology unit on animal dissection.
Central to this rite of passage were the smells and occasional screams signifying a classroom out of control; the unforgettable sight of a freezer-burned rhesus monkey that had been thawed and iced at least once too often; and the wise guys in class at the corner dissection table who would surgically remove the webbed foot of a bullfrog, then secretly place it like a bookmark inside the text of an unsuspecting classmate.
Now, a debate over the best method to lead students through one of the most touchy areas of science education is under way across the country.
The catalyst is an emerging library of laserdisc and CD-ROM programs that can replace the slice of a scalpel with the click of a mouse for students who are squeamish or morally opposed to pulling back the skin of a bullfrog in a surgical quest of oviducts and eggs.
Another factor in the push for computer dissection - a tool that until recently was available only at leading medical schools - is a heightened awareness about endangered species and strong opinions about animal rights among young people.
Software programs with names like “Virtual Frog” and “MacInvertebrate” offer the closest-ever approximation to the real thing. These programs are becoming a part of the supplemental curriculum, and some argue they should be offered as an alternative to regular dissection at schools that can afford the technology.
The teach-and-test formats use a gamelike setting that in “MacFrog” includes a “ribbit” cheer for correct answers and color QuickTime movies of skeletal, reproductive and digestive systems.
But that is not real enough, say critics who are concerned how the nation’s future physicians and researchers will fare if animal cadavers give way to one-dimensional computer models in which a tweezer on the screen is used to place virtually dissected matter into a petri dish.
“For me, there’s no substitute for having your hands inside a dead organism,” said Wayne Carley of the National Association of Biology Teachers. “You can memorize all the beautiful CD-ROM pictures of muscles and bones you want, but the minute you start looking inside that animal, it becomes clear the organs aren’t really color-coded.”
At its annual meeting in Phoenix later this month, the 8,000-member National Association of Biology Teachers board of directors will reaffirm its position favoring the dissection of dead animals for instruction.
The Human Anatomy and Physiology Society in July also adopted a strong pro-dissection policy statement.
“A fundamental tenet of science is careful and thoughtful observation by the investigator,” said Bob Anthony, the society’s president and an instructor at Triton College in suburban River Grove, Ill. “Models and computer programs should not be considered as equivalent alternatives.”
Both associations favor allowing students to choose ultimately whether to participate in dissection labs, a policy followed across the country and by most school districts in Illinois, according to the state education board.
“To be honest with you, everyone wants to dissect. Every year or so we have one or two students who object,” said Diane Norwalk, a biology teacher at Glenbrook South High School in Glenview, Ill. “And with the computer, that’s OK because we can still hold them responsible for the material.”
As Norwalk spoke, students Elizabeth Wengel and Scott Pucci practiced their motor skills as well as their social skills.
“Whoa, whoa, don’t stick the scalpel in so far,” Wengel, 14, advised, concentrating her attention on a bullfrog lying in a tray. “Cut the skin back more.”
“I’ve cut as far as it can be cut, because of the membrane,” Pucci, 15, responded, flexing the fingers of his plastic-gloved hand. “Don’t worry about it, Liz. I’ll get some forceps working on it.”
Computer-assisted dissection is gaining popularity as a supplemental tool - particularly in schools in Chicago’s north and west suburbs - but it is not likely to supplant the traditional method, officials said.
Biology instruction, however, has shown a new respect for lab animals, from the planarian to the cat.
“We spend a lot of time beforehand discussing our philosophy in dissection and why we’re doing it,” Norwalk said. “I always remind the students that a lot of the research on frogs, from what they eat to how their habitat is being restored or destroyed, is being done to save them.”