lecture 4 Flashcards
taxonomy
the naming and classification of organisms
systematics
classification of organisms based on evolutionary relationships (phylogenies)
phylogeny
hypothosis about patterns of evolutionary relationships, represents actual evolutionary history
phylogenetics
the reconstruction and study of evolutionary relatonships, goal of phylogenetics is to make classification portray real history of evolution
charactors
trait we are using to contruct tree, can be number of toes, bp in DNA
outgroups
more distantly related organism that serves to root a tree, intentionally included even tho you know its not closely related
derived character state
a character state shared by a group of OUTs that is not the ancestral state (absent in ancestors)
synapomorphy
shared derived character state
homoplast
difficulty of constructing a tree, independent evolution of similar traits that is a result of convergent evolution or evolutionary reversal
evolutionary reveral
return to an earlier character state like penguins not being able to fly
rapid diversification
difficulty of constructing a tree, tree of more species arising during a short period of time
Incomplete lineage sorting
occurs when ancestral gene copies fail to coalesce into a common ancestral copy until deeper than previous speciation events, rapid diversification
adaptive radiation
evolution of a group into a wide variety of species each adapted to specialized conditions, rapid diversification, species colanize an area
introgression
difficulty of constructing a tree, movement of genes from one species or population into another by hybridization and backcrossing, some genes in genome undergo this some don’t, may also occur through horizontal gene transfer, semi porus boundarys
monophyletic group
represents a single evolutionary group containing the ancestor and all its descendants
