Chapter 25 Flashcards
Tools for studying history- Phylogenetic tree
Ancestral Trait
A trait found in the ancestors of a particular group
Tip
Represents the descendants of ancestors in a phylogenetic tree
Homology
Similarity among organisms of different species due to shared ancestry. Features that exhibit such similarity are said to be homologous
Monophyletic Group
An evolutionary unit that includes an ancestral population and all of its descendants but no others. (also called a clade or lineage)
Branches
Parts of a phylogenetic tree that represents populations through time
Homoplasy
Similarity among organisms of different species due to reasons other than common ancestry, such as convergent evolution
Nodes
the point where 2 branches diverge, representing the point in time when an ancestral group splits into 2 or more descendant groups
Parsimony
Suggests that, when comparing phylogenetic trees, one required the fewest character changes is most likely
Root
Represents the ancestral lineage in a phylogenetic tree.
Polytomy
A node in a phylogenetic tree that depicts an ancestral branch dividing into 3 or more descendant branches; indicates insufficient data were available to resolve which taxa are more closely related.
Derived Trait
A trait that is a modified form of an ancestral trait, found in a descendant
Synapomorphy
A shared, derived trait found in 2 or more taxa that is present in their most recent common ancestor but is missing in more distant ancestors. Useful for inferring evolutionary relationships
Outgroup
A taxon that is closely related to the taxa being studied, but that diverged earlier; a sister group to the group being studied.
Polyphyletic Group
An unnatural group based on convergent (homoplastic) characteristics that are not present in a common ancestor.
