Phylogenetics and Phylogeography Flashcards
What does a cladogram show?
Only relative ancestry. Neither axis means anything.
What does a phylogram show?
It quantifies the amount of change. Branch lengths indicate “how close” taxa are to each other. X axis means nothing; Y axis shows amount of change.
What does a dendrogram show?
Relative ancestry according to a molecular clock. Evolutionary time is quantified along the Y axis. The X axis means nothing.
How do rooted trees differ from unrooted trees?
Rooted trees have a node identified as the root from which all other nodes descend. This gives us an evolutionary time axis.
Define parallel evolution.
Independent evolution of the same feature from the same ancestral condition.
Define convergent evolution.
Independent evolution of the same feature from a different ancestral condition.
Define secondary loss.
Reversion to ancestral condition.
What is a monophyletic taxa?
A taxa containing a common ancestor and all of its descendants.
What is a paraphyletic taxa?
A taxa containing the most recent common ancestor but does not contain all the descendants of that ancestor.
What is a polyphyletic taxa?
A taxa that does not contain the most recent common ancestor of all the members.
What is the homoplasy headache?
Organisms can show identical characters due to homoplasy not recent ancestry. Identical by state, not identical by descent.
Define phylogeography.
The correlation between intraspecific genetic diversity and geographic features and the divergence of populations within species.
What are adaptive radiations of species?
A form of rapid speciation within a lineage.
Define microevolution.
Changes in allele frequencies within populations/species.
Define macroevolution.
Long term processes of divergence among higher-level taxa.
