Chapter 5 Determining Evolutionary Relations Phylogeny Outgroup Species

• Scientist organize species into categories that indicate how closely related they are

Phylogeny • Species relatedness is based on similarity of their traits • The more

Phylogeny • Morphological traits, behavior and genetic similarity are all used in constructing phlogenetic

Tree of life Why is phylogeny important? Understanding and classifying the diversity of life

Phylogeny What is a phylogeny? Branching diagram showing relationships between species (or higher taxa)

Phylogeny Terminal nodes = contemporary taxa Internal nodes = ancestral taxa

Phylogeny and classification Hierarchy Phylogenetic (cladistic) classification reflects evolutionary history The only objective form

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Chapter 5 – Determining Evolutionary Relations Phylogeny Outgroup Species A Species B Species C AAGCTTCATAGGAGCAACCATTCTAATAATAAGCCTCATAAAGCC AAGCTTCACCGGCGCAGTTATCCTCATAATATGCCTCATAATGCC GTGCTTCACCGACGCAGTTGTCCTCATAATGTGCCTCACTATGCC GTGCTTCACCGACGCAGTTGCCCTCATGATGAGCCTCACTATGCA

• Scientist organize species into categories that indicate how closely related they are to one another. • Phylogenies – are the branching patterns of evolutionary relationships • Phylogenetic tree – is a diagram that shows this branching pattern

Phylogenetic Tree

Phylogeny • Species relatedness is based on similarity of their traits • The more similar the traits, the more closely related the two species are assumed to be

Phylogeny • Morphological traits, behavior and genetic similarity are all used in constructing phlogenetic treats

Tree of life Why is phylogeny important? Understanding and classifying the diversity of life on Earth Testing evolutionary hypotheses: - trait evolution - coevolution - mode and pattern of speciation - correlated trait evolution - biogeography - geographic origins - age of different taxa - nature of molecular evolution - disease epidemiology …and many more applications!

Phylogeny What is a phylogeny? Branching diagram showing relationships between species (or higher taxa) based on their shared common ancestors Species: A B D E F E Time C A B C F D Time A and B are most closely related because they share a common ancestor ( call the ancestor “E”) that C and D do not share A+B+C are more closely related to each other than to D because they share a common ancestor (“F”) that D does not share

Phylogeny Terminal nodes = contemporary taxa Internal nodes = ancestral taxa

Phylogeny and classification Hierarchy Phylogenetic (cladistic) classification reflects evolutionary history The only objective form of classification – organisms share a true evolutionary history regardless of our arbitrary decisions of how to classify them Phylogeny Classification Family Genus Order Family Genus Class Family Genus Order Family Genus