Two main approaches to determine relationships between species?
Morphological characteristics; Molecular characteristics
Define morphological characteristics.
Comparison of size, shape, and anatomical features.
Define molecular characteristics.
Comparison of DNA and protein sequences.
What is a phylogenetic tree?
Hypothesis showing evolutionary history; nodes = common ancestors.
What is tree topology?
Branching pattern of a phylogenetic tree.
What is a basal taxon?
Lineage that diverges early from the rest.
What is phylogenetic bracketing?
Predict traits of extinct organisms using living relatives.
Example of phylogenetic bracketing?
Dinosaurs predicted to have nests, singing, brooding.
Phylogeny vs Systematics?
Phylogeny = evolutionary history; Systematics = classification + relationships.
Linnaean hierarchy?
Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species
Define homology.
Similarity due to shared ancestry.
Define analogy.
Similarity due to convergent evolution.
What are molecular homoplasies?
Shared DNA without close relationship; independent origin.
What is molecular systematics?
Using molecular data to infer relationships.
Why do sequences differ in length?
Insertions/deletions accumulate over time.
What is a clade?
Ancestor + all descendants.
Monophyletic group?
Ancestor + all descendants.
Paraphyletic group?
Ancestor + some descendants.
Polyphyletic group?
Members lack shared immediate ancestor.
Shared ancestral character?
Trait originating before clade.
Shared derived character?
Trait unique to clade.
Why isn’t backbone a derived mammal trait?
It predates mammals → ancestral.
What is an outgroup?
Lineage diverged before ingroup.
How are outgroups used?
Traits shared with outgroup = ancestral.
