Can’t Beet This

I conducted this project as part of Professor Pringle’s EEB321 class at Princeton University.

What is this strange molten sphere? Is a star? Or perhaps a ball of hot metal?

It is, in fact, something much more interesting. It is a beet. Or rather — a very thin slice of a beet under magnification in a foldscope.

As I began my investigations with the foldscope, I started in my kitchen, examining first a slice of green onion, and then afterward, a slice of beet.

After I’d produced this image of the beet, I found myself interested in why this plant, or specifically its taproot, was so ferociously colourful. I thought about other root vegetables that were comparably dull — potatoes and parsnips, for example. I also thought about counter examples of more colourful root vegetables — carrots, for instance.

Was this colouring a mere side effect of other nutrients the plant was storing in its roots, the result of artificial selection by humans, or the product of another explanation?

An initial internet search brought me to a New York Times Article, How Beets Became Beet-Red (https://www.nytimes.com/2017/10/24/science/beets-red-enzymes.html), which shed some light on the question. In terms of what advantageous purpose the colouration served, the article suggested that the scientific community is uncertain. It’s possible that the colouration, which does affect other parts of the plants, was effective in attracting pollinators. It’s also possible that the responsible compound confers other advantageous properties, including improved resilience to weather stress.

Nonetheless, the mystery of the beet’s red colour remains, a reminder of the beautiful challenge of humanity’s study of the evolutionary past. We live amid the result of billions of years of evolution on earth. Unlike so much of what humanity studies, we cannot watch evolution as it created the beet. We can attempt to understand that process with experiments and inference, but we ultimately stand like a detective on a crime scene, trying to piece together a story we did not witness.

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P.S. I should elaborate that while we don’t have the luxury of watching the beet evolve, there are other instances where biologists have been able to see evolution in complex organisms firsthand — not least of which, finch differentiation in the Galapagos.

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