[Campbell Biology P.606] What does it mean for a phylogenetic tree to be "rooted," and what ... | Practice Question
What does it mean for a phylogenetic tree to be "rooted," and what is a "basal taxon" within such a tree?
A: A rooted tree indicates the exact time of divergence, and a basal taxon is the most phenotypically similar organism.
B: A rooted tree has a branch point representing the most recent common ancestor of all taxa, and a basal taxon is a lineage that diverges early from other members.
C: A rooted tree means its branches cannot be rotated, and a basal taxon is always the oldest living species in the group.
D: A rooted tree implies a sequence of evolution from left to right, and a basal taxon is the most recently evolved species.
Explanation
As stated in the text, a 'rooted' phylogenetic tree has a branch point representing the most recent common ancestor of all taxa in the tree. A 'basal taxon' is defined as a lineage that diverges from all other members of its group early in the history of the group.