Interesting article, but only mentions 'carbon' once:

> " Tracer experiments supported the notion that nitrogen, likely in the form of ammonium, is separated from the carbon skeleton of glutamate in digestive fluid (Fasbender et al., 2017). In multiple carnivorous plants, ammonium transporters (AMTs) appear to play pivotal roles in ammonium uptake."

The fundamental difference is that plants tend to use atmospheric CO2 for their carbon source, while the digestive tracts of animals are optimized for the uptake of sugars, fats and proteins for both energy and carbon feedstock purposes.

These systems of carnivorous plants are probably optimized to extract the CHOPKNS_CaFe elements from their prey that they can't get from the atmosphere.

I find it so fascinating that these plants developed carnivorous characteristics across totally separate lineages, geographies and timelines.

I also read somewhere that plants have gone in and out of carnivory (through the process of millions of years of adaptation, of course).

Glandular cell evolution is truly unique. These cells in carnivorous plants have evolved to secrete digestive enzymes that help the plants digest prey. Their evolution is thought to have arisen independently in at least six different plant families, including the Droseraceae, Nepenthaceae, Sarraceniaceae, Lentibulariaceae, Cephalotaceae, and Roridulaceae. Not only that, but the glands in different carnivorous plants can be highly specialized depending on the type of prey they capture. For example, the pitcher plants of the Nepenthaceae family have glands that secrete a nectar-like substance to attract prey, while the sundew plants of the Droseraceae family have sticky glandular hairs that trap insects. Their evolution is an example of convergent evolution, where unrelated species evolve similar traits independently in response to similar ecological pressures. Funky Dung this science stuff!