Evolution for Breakfast

Banana.jpg
Every bite comes fortified with deep history

You wake up hungry and head straight to the table. This morning you’re having cinnamon coffee, toast with chocolate-hazelnut spread, hash browns, and a banana. Still sleepy, you’re grateful that both coffee and chocolate contain caffeine. Wait, is that because they’re closely related? You look it up. Nope. Chocolate is in the cotton family (you tug absentmindedly at your t-shirt), and fairly close to the hazelnuts that also compose your Nutella. Meanwhile, the closest thing to coffee in your meal are the potatoes. What about the banana? In your head you always grouped it with coffee and chocolate as an exotic tropical crop. It turns out the banana is far from both of them in the clan of your bread’s wheat, which is of course a type of grass. So is sugar. Cinnamon is the last ingredient you Google. You learn that it’s a very distant relative of everything else in your meal, far from almost all fruits and vegetables, and closer to nutmeg. Pumpkin spice diverged from pumpkins over 100 million years ago. This is exciting! You’re not sleepy anymore. You never bothered to wonder before how your own food fits into the tree of life. It’s like a puzzle. The familial relationships among species is known as phylogeny. The fruit in your mouth is kin with the crust on your plate, and, ultimately, with you and the rest of the world. Sated, you save half of the banana for lunch.

At noon, you add the banana to a fruit salad with apples and oranges. You eat it with some chicken wings, broccoli, and coleslaw. The broccoli and cabbage have the same mustardy bite. Are they closely related? Skeptical because of the caffeine thing, you are again surprised. More than just cousins, you discover they are actually the same species, along with Brussels sprouts and kale. The taste of their shared chemical composition betrays their kinship. You start to pick at your fruit salad. A banana has five sides. Apples and oranges, cut across their equators, also usually show five-part symmetry. Coincidence? Apple and oranges aren’t exactly siblings, but they’re close enough that it could be a shared developmental pattern. Bananas, you recall, are way out there with the grasses, and probably evolved their pentagonal shape independently. You pick up a chicken wing. The bones in the wing are the same as the bones in the hand holding it: carpals, metacarpals, phalanges. Both are descended from the fragile paw of a lizard-like critter foreshadowing birds and mammals. If two bodily features share the same origin story, they show homology. Like phylogeny, homology is right there on your table. That is, until most of it is in your gut. The vegetables taste too similar to each other, so you save the cabbage for supper.

Supper is tacos with cheese, cabbage, salsa, and guacamole. Your mouth burns from the chilis, not to mention that same sulfury cabbage. Why does spice exist, anyway? The cabbage has evolved a chemical defense against insect pests. The capsaicin of peppers is a deterrent, too, though a more counterintuitive one. After all, a pepper is a fruit, and fruits exist to be eaten in order to spread seeds. It so happens that the pepper’s preferred seed couriers, birds, can’t taste the heat. The burn targets undesirable herbivores, including us mammals. Other fruits do solicit shaggy partners. Your guacamole grew from a pit so large, neither African nor European swallow could transport it. Yet it did adapt to a swallow: specifically, being swallowed by extinct mega-beasts like giant ground sloths. You thank the farmers who have kept it alive over the centuries with no help from modern wildlife. Species don’t just change randomly, they fit themselves to a particular way of life in a certain environment. Molding yourself to your habitat is called adaptation. As you chew your melted cheddar, you recall that your species, too, has adapted. The dairy industry is only possible because some adult humans, unlike most adult mammals, can digest the lactose of milk. Lactose tolerance is younger than agriculture itself, and only became so common because it was adaptive. You stare at the reds, greens, and oranges nestled in your tortilla. The fact that we can even see so many colors is a primate adaptation for eschewing the nocturnal, scent-driven lifestyle of our scurrying ancestors. You fit your food and your food fits you. The diversity of culinary flavors, textures, and colors, not to mention sheer edibility, arises from adaptations in both the food organisms themselves and in our own bodies.

Phylogeny for breakfast, homology for lunch, adaptation for supper. Evolution’s harvest is all around us, and you shovel it into your gullet every day. Unless you live on a farm or in a Disney movie, it’s likely that your most vivid daily interactions with other organisms are at mealtime. It’s the best opportunity to dig deeply into that fertile garden in which we are rooted. Once you wake up to the natural history in your kitchen, there’s no end to the exploration. What family are avocados in, anyway? Wait, they’re actually grouped with cinnamon? You save some for tomorrow. Maybe huevos rancheros for breakfast.

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