​​​Each colour in the above Web of Life represents high order taxa we know today:

• Blue and Red depict Bacteria and Archaea (which together make up the Prokaryotes)

• Yellow serves as a placeholder, indicating the Eukaryotes - starting at their endosymbiotic origins (a merger), until they evolved into their contemporary kingdoms shown in new colours.

• Green, Orange, White, and Brown depict the Plants, Animals, Fungi, and Protists

​​​

Note how the plants and their closest relatives had another endosymbiotic merger along their evolutionary journey!

 

​Note also how the Protists are ubiquitous across the threads of of the web of life - you could consider changing all the yellow into brown to show how Plants, Animals, and Fungi emerged from a slurry of Protists. But the modern, distantly related threads that make up the Protists are as long running in their evolution as the big three (Plants, Animals, and Fungi).  This, to me, warrants a differentiation from their ancestors. 

​

Protista is not, however, a 'clean' biological grouping. Protista is a traditional term that, rather than pointing to the similarities of its members, points to how they are distinctly different from the big three discussed earlier. Some refer to Protista as as the "junk drawer" of taxonomy - its where we put things when we don't quite know where else to put them. While it's not a 'clean' grouping, the creation of a paraphyletic group keeps the depiction clean, and lets us talk about the big three.