I just finished reading Turtles All the Way Down, a young-adult novel by John Green. It’s written from the perspective of a high school student named Aza who has obsessive-compulsive disorder and who specifically obsesses about the bacteria that are in and on her body.
Green, who deals with an OCD-related obsession that’s similar to his protagonist’s, uses some inspired biological metaphors to show what it’s like to have thoughts you struggle to prevent yourself from thinking. GROSSNESS ALERT! One extended metaphor involves a parasite that spends part of its life cycle in the eye of a fish and greatly influences the fish’s behavior—making it slower moving and more cautious—to increase the odds the parasite will survive until it’s sexually mature. Because the parasite reproduces only in the digestive tract of a fish-eating bird, once it’s ready to have sex, the parasite makes the fish swim closer to the surface and with less caution, thereby increasing the odds its host will get consumed by a piscivorous bird. Aza compares herself to that fish: incapable of controlling her behavior and feeling “like my whole story was written by someone else” (page 106).
Aza also uses an invasive species metaphor to characterize her obsessive thoughts:
I have these thoughts that [my therapist] Dr. Karen Singh calls “intrusives,” but the first time she said it, I heard “invasives,” which I like better, because, like invasive weeds, these thoughts seem to arrive at my biosphere from some faraway land, and then they spread out of control.
In the Fresh Air interview I linked to above, Green said he misheard “intrusives” as “invasives” when he was younger, and he still has questions about how much sovereignty he has over his own life.
If I had read TATWD before it was published, I would have suggested changing “biosphere” to “ecosystem” in the passage above, which is on page 45. The biosphere is “the portion of the planet capable of supporting life,” according to The Dictionary of Ecology and Environmental Science. An ecosystem is a smaller entity: “a functioning unit of nature that combines biotic communities and the abiotic environments with which they interact.” Metaphorical “invasive weeds … from some faraway land” would have come from the same metaphorical “biosphere” as Aza but a different metaphorical “ecosystem.”
Ecology, by the way, is “the branch of biology that studies the relationships among living organisms and between organisms and their environments.” Like the word economics, ecology is derived partly from the Greek word oikos, which means house.
And speaking of living organisms, Aza spends some time in her narration talking about the tuatara, a fascinating reptile native to New Zealand that is lizard-like but is classified as the only surviving member of its own distinct order, Sphenodontia/Rhynchocephalia. Tuatara can live for at least 150 years. And tuatara is both the singular noun and its plural (page 36). Tuatara can be a host for parasites without being sickened by them (page 175). Based on the fossil record, they don’t seem to have changed much in the past 200 million years. They aren’t fully grown until they’re 30 years old. Females lay eggs only every four years. And they have a slow metabolic rate but a faster rate of mutation than any other animal that’s been studied (page 177).
I recommend TATWD. The mystery aspect of the story was pretty weak and basically just involved figuring out what a missing man meant by a cryptic phrase he conveniently left in a note on his abandoned mobile phone. But the relationships between the characters were what mattered to me, and they were so skillfully described, I’d gladly read a sequel.