Biology 1001A Lecture Notes - Lecture 20: Autapomorphy, Gene Regulatory Network, Synapomorphy
7 Mar 2016
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Out-group comparison relies on parsimony simplest explanation is best. Whichever tree requires the fewest evolutionary changes (gains or losses of a trait) is probably correct. Can use parsimony if we have multiple phylogenetic trees and don"t know how to evaluate them. Shark is less closely related to any of the in-group members. Shark being less closely related to ingroup members than ingroup members are to w. o. They differ in terms of whether the bat is more closely related to chipmunk or chicken. Look at traits of members of ingroup to evaluate the 2 phylogenies. To evaluate which of the two phylogenies, see which species has more common traits = more parsimony. Most parsimonious explanation: common ancestor of sharks did not have wings. Lactation is shared and derived (found in bat and chipmunk) Answer: no, only one of these groups is unique and derived, not shared.
