How to understand phylogenetic tree’s patterns

Monophyletic Groups: A monophyletic group, also known as a clade, consists of an ancestor and all of its descendants, sharing a common ancestry that is not shared with any other group. This type of grouping is considered to represent true evolutionary relationships, as it includes all members descended from a single common ancestor without excluding any. It represents a complete lineage in the tree of life. Paraphyletic Groups: A paraphyletic group includes a common ancestor and some, but not all, of its descendants. This means that while the group is based on a common ancestor, it arbitrarily excludes one or more descendants that have gone on to form other lineages. These groups are often identified based on shared characteristics that have been lost or modified in the excluded members. Paraphyletic groups do not accurately reflect the full evolutionary history because they leave out some descendants of the common ancestor. Polyphyletic Groups: A polyphyletic group is formed based on similar characteristics but does not include the most recent common ancestor of all the members in the group. These groups may appear similar due to convergent evolution (where unrelated species evolve similar traits independently) or other reasons, but they do not share a direct common ancestry within the group. Polyphyletic groupings are not considered natural in terms of reflecting evolutionary relationships because they do not accurately represent patterns of descent from a common ancestor.