> The exact list is up for debate, and currently undergoing change.
My strong impression is that even the roots of the tree are debated, with competing models that often change.
> The four-kingdom system should have died out decades ago
First, hopefully not! :) Second, I think it's used because it's the last stable model. Third, it's a model that the public can understand - theres no point in even trying to use "Archaeplastida, Excavata, SAR supergroup, Amoebozoa, and Opisthokonta" unless you are an expert in phylogenics or evolution. Who can understand and remember that?
My strong impression is that even the roots of the tree are debated, with competing models that often change.
> The four-kingdom system should have died out decades ago
First, hopefully not! :) Second, I think it's used because it's the last stable model. Third, it's a model that the public can understand - theres no point in even trying to use "Archaeplastida, Excavata, SAR supergroup, Amoebozoa, and Opisthokonta" unless you are an expert in phylogenics or evolution. Who can understand and remember that?