Tree Thinking & Phylogenetic Trees
Key Terms
• Phylogeny
• Phylogenetic trees
• Tree of life
• Anatomy of a tree – branch, node, tip, outgroup, root, sister group
• Character & character state
• Ancestral v derived v convergent traits and similarities
• Synapomorphy
• Monophyletic group v Clade, Lineage, Taxon
• Parsimony
• Homology v Homoplasy
• Homologous v Analogous (Convergent)
Codon Objectives:
• Given a phylogeny and information about a trait in the species included, mark the tree to
indicate where changes in the trait occurred.
• Given a phylogenetic tree,
1) label the root, nodes, branches, and tips;
2) identify the type of taxon at the tips (e.g., species or larger group),
3) circle and label several monophyletic groups, at least two of which are nested,
4) state at least one synapomorphy that identifies each of the circled monophyletic groups,
5) find the most recent common ancestor of any two given taxa.
Additional Objectives:
• Interpret the relationships between lineages on a phylogenetic tree
How do we visualize speciation happening?
o Something happens to a population and they split due to something in time but
when they split they become independent of each other. This creates a
phylogenetic tree.
Ex.
,
o Sister groups C and D
NOT B and C
Monophyletic group: an ancestral population and all descendants
o Synapomorphy: trait unique to a monophyletic group
Character: given feature you're using (ex. flower color)
State: what specific version of that character does the species have? (which specific colors are
they?)
Ancestral similarity: homology, they look the same as there ancestor because they have shared
state
Derived similarity: new shared state; its recent (ex. If something changes on the tree and a
different monophyletic group has different derived similarity
Convergent Similarity: unrelated shared state, they look similar but the other half had a change
Outgroup- an existing that is more ancestral than your central species
How do we define species?
o Species = an evolutionarily independent population or group of population
Latin word meaning "kind" or "appearance"
Key Terms
• Phylogeny
• Phylogenetic trees
• Tree of life
• Anatomy of a tree – branch, node, tip, outgroup, root, sister group
• Character & character state
• Ancestral v derived v convergent traits and similarities
• Synapomorphy
• Monophyletic group v Clade, Lineage, Taxon
• Parsimony
• Homology v Homoplasy
• Homologous v Analogous (Convergent)
Codon Objectives:
• Given a phylogeny and information about a trait in the species included, mark the tree to
indicate where changes in the trait occurred.
• Given a phylogenetic tree,
1) label the root, nodes, branches, and tips;
2) identify the type of taxon at the tips (e.g., species or larger group),
3) circle and label several monophyletic groups, at least two of which are nested,
4) state at least one synapomorphy that identifies each of the circled monophyletic groups,
5) find the most recent common ancestor of any two given taxa.
Additional Objectives:
• Interpret the relationships between lineages on a phylogenetic tree
How do we visualize speciation happening?
o Something happens to a population and they split due to something in time but
when they split they become independent of each other. This creates a
phylogenetic tree.
Ex.
,
o Sister groups C and D
NOT B and C
Monophyletic group: an ancestral population and all descendants
o Synapomorphy: trait unique to a monophyletic group
Character: given feature you're using (ex. flower color)
State: what specific version of that character does the species have? (which specific colors are
they?)
Ancestral similarity: homology, they look the same as there ancestor because they have shared
state
Derived similarity: new shared state; its recent (ex. If something changes on the tree and a
different monophyletic group has different derived similarity
Convergent Similarity: unrelated shared state, they look similar but the other half had a change
Outgroup- an existing that is more ancestral than your central species
How do we define species?
o Species = an evolutionarily independent population or group of population
Latin word meaning "kind" or "appearance"
