BIOL 2040 Lecture Notes - Lecture 15: Amniotic Sac, Amnion, Amniote
9 Apr 2016
School
Department
Course
Professor
Document Summary
A taxon that you know is more distantly related to any of the taxa than they are to each other: character trait shared with outgroup is said to be ancestral. Phylogenies of terrestrial vertebrates: outgoup: amphibian not an amniote amnion shared with all terrestrial vertebrates. Amphibians can"t reproduce out of water due to lack of amnioic sac. Amnion is the synapomorphy in all terrestrial vertebrates. Add a second trait to begin further spliing the amniotes o. But, mammals and birds having a the closest common ancestor is not accurate know birds share a common ancestor with repile: and more traits . One temporal opening and two openings were separate evoluions both arose from no openings. Parsimony and judgement puing it all together. Idenify synapomorphy: shared, derived characters that arose in a common ancestor and are present in descendants. Resolve conlicts with parsimony: the fewest number of evoluionary steps is most likely the correct phylogeny.
