Phylogeny Flashcards
classification of organisms based on how they are related to one another evolutionary
phylogeny
the scientific discipline of classifying and naming organisms
taxonomy
any unit within a taxonomy
taxon (pl. taxa)
How is phylogeny expressed?
as a tree diagram
What type of data can phylogeny include?
phenotypic/genetic data
What type of traits MUST phylogeny be based on?
homologous
What taxonomic level is phylogeny present at?
any/all
Phylogeny at its core is just an ___.
hypothesis
phylogenetic grouping consisting of the ancestor species and all descendants
monophyletic
phylogenetic grouping consisting of an ancestor but not all descendants
paraphyletic
phylogenetic grouping consisting of various taxa with different ancestors
polyphyletic
similarity due to shared ancestry
homologous traits
similarity due to convergent evolution
analogous traits
when similar selection pressures result in similar adaptations among different evolutionary lineages
convergent evolution
What are the 2 key concepts of phylogeny?
shared derived trait & maximum parsimony
an evolutionary novelty unique to a monophyletic group
shared derived trait
the tree that requires the fewest evolutionary events is the most likely
maximum parsimony
What is the purpose of molecular clocks?
(1) date trees beyond fossil record
(2) assume a constant rate of DNA evolution
(3) rate is proportional to time since a common ancestor
(4) estimate the absolute time of evolutionary change
What are the problems with molecular clocks?
(1) DNA sequences evolve at different rates
(2) evolution can be irregular within a gene/sequence
(3) use of multiple genes may improve estimates
(4) use of certain types of genes can improve estimates
(5) high degree of uncertainty
What use are phylogenies?
(1) identify species
(2) go from raw genetic data to hidden histories of the species and world
(3) predict features of extinct species based on features of closely living relatives
