what is the difference between monophyletic taxon, a polyphyletic taxon, and a paraphyletic taxon
A monophyletic taxon is a group that includes an ancestor and all of its descendants. It represents a single evolutionary lineage and is considered a natural grouping. In other words, all members of a monophyletic taxon share a common ancestor.
A polyphyletic taxon, on the other hand, includes organisms that do not share a common ancestor. It is a grouping that has been assembled based on superficial similarities rather than shared evolutionary history. Polyphyletic taxa are considered artificial groupings and are not valid in evolutionary biology.
A paraphyletic taxon includes an ancestor and some, but not all, of its descendants. It represents an evolutionary grouping that excludes certain descendants of the original ancestor. Paraphyletic taxa are considered incomplete and are usually not recognized as valid taxonomic groups, as they do not accurately reflect the true evolutionary relationships among organisms.