We usually imagine plants to be peaceful, quiet organisms thriving on water, sunlight, and the occasional sprinkling of fertilizer. We may think of them as sources of food, or clothing, or simple decoration. Some plants are less cooperative, however, having developed complicated strategies for the capture and digestion of protozoa, insects, and even small invertebrates. These mechanisms can be passive, like the sticky or slippery appendages of the sun dew and pitcher plants, or as active as the snapping shut of the Venus flytrap and waterwheel plants. In fact, while carnivory is certainly an unusual trait in plants, it is far from a trivially rare adaptation, and has evolved independently in several plant lineages. How and why these different kinds of carnivorous plant species developed a similar taste for “more advanced” organisms remains a mystery.
Because many carnivorous plants are found in bogs and marshes, one theory is that they were forced to develop these kinds of coping mechanisms in the face of low-nutrient, swampy environments that are inhospitable to photosynthesis. We don’t know precisely how gradual evolutionary change led to this adaptation, though. What kind of leaf-tip mutation would have conferred sufficient advantage, such that the vacuum trap of the bladderworts could have begun to develop? And how did the necessary digestive juices and metabolic processes for carnivory happen to arise at the same time? Suffice it to say, some plants have bucked their traditional reputation as harmless food, instead taking on a more predatory role.
Text by Margaret Smith with illustration by Jim Stoten
As featured in the Spring 2017 Edition of Beekman 1802 Almanac Magazine. For more check out The Where, the Why, and the How: 75 Artists Illustrate Wondrous Mysteries of Science published by Chronicle Books 2012.