BIS 2C Lecture 2: BIS 2C Lecture 2
9 Jan 2019
School
Department
Course
Professor
Document Summary
Relationships on trees are unaffected by the rotation of nodes. Because a and b share a node (mrca), rotation has no affect on their relationship. The same rule holds true for c and d. because they share a node, there is no effect on relationship. Every node is free to rotate, including the root node. Rotating nodes make the tree appear different, but relationships among taxa are unaffected . Monophyletic group (aka natural group or clade) : a group of organisms consisting of their most recent common ancestor (mrca) and all of its descendants. We do not refer to monophyletic clades" as clades by definition are monophyletic. 7- determined by counting the number of nodes. A group of organisms that either: excludes descendants of a mrca (most recent common ancestor, combines organisms that lack a mrca. Paraphyletic groups include the mrca but exclude one or most descendants. Polyphyletic groups combine organisms that lack a mrca.
