I posted this somewhere else, but am reposting it here because there wasn't much traffic where I posted it the first time.
I think SciShow should do a video comparing and contrasting Linnaean taxonomy and Phylogenetics.
The short of it is that originally, Linnaeus assigned each living things into 7 layers of classification. Phylum, class, order, family, genus and species. It soon became clear that 7 was not nearly enough ranks, taxonomists just kept adding layers, such as super-order, infra-order etc. Eventually it became clear that there are no ranks in nature, so they threw out the ranks all together and created a system which uses an arbitrary number of divisions called Phylogenetics. The divisions in phylogenetics occur when a lineage of organisms diverged into separate species, making it far superior to Linnaeus' method of assigning groups into arbitrary layers.
There are some extremely common misconceptions about the nature of evolution taxonomy that arise from the use of Linnaean taxonomy. One such misconception is that, addressed on SciShow before, is that birds are not dinosaurs. In fact, they are, because birds have a direct ancestor that certainly is a dinosaur. In the same way, humans certainly are both apes and monkeys. Not only do we fit all of the required morphological characteristics, we also share direct ancestors that are definitely apes and ancestors that are definitely monkeys.
So yeah. Some rich material there. What do you think? Are there any other topics that you think would be important to cover?