Final answer:
The branch point at the root of a phylogenetic tree represents the most recent common ancestor of all species, often called the last universal common ancestor (LUCA). Sister taxa represent a more recent divergence from a common ancestor. The most recently evolved organisms are at the ends of the tree's branches.
Step-by-step explanation:
The branch point that represents the most recent common ancestor of all species on a phylogenetic tree is the one located at the root of the tree. This point indicates where the ancestral lineage gave rise to all organisms represented in the diagram. The root is often referred to as the last universal common ancestor (LUCA). On the other hand, sister taxa emerge from a branch point that is more recent than the root, where two lineages diverge from a common ancestor. In contrast, the organisms that have evolved most recently would be found at the ends of the outermost branches of the tree.