BIO SCI 94 Chapter Notes - Chapter 28: Phanerozoic, Radiometric Dating, Synapomorphy

• School: UC-Irvine
• Department: Biological Sciences
• Course: BIO SCI 94
• Professor: Robin Bush

Document Summary

Chapter 28 phylogenies and the history of life. 28. 1 tools for studying history: phylogenetic trees. Phylogeny - evolutionary history of a group of organisms. Phylogenetic tree - graphical summary of evolutionary history, showing ancestor- descendant relationships among populations, species, or higher taxa, and clarifying who is related to whom. Effective at summarizing data and testing hypotheses. Branches on left are more ancestral while those on the right are most recent. Nodes represent hypothetical common ancestors; taxa located on tips, and not presumed to be ancestors of others. Tree of life -most universal phylogenetic tree, depicting evolutionary relationships among all living organisms on earth. First step in inferring evolutionary relationships = decide which populations, species, or higher taxa to compare and which characteristics to use. Character - any genetic, morphological, physiological, or behavioral characteristic to be studied. Outgroup - species closely related to group being studied, but not part of it; used to establish whether character state is ancestral or derived.