Phylogeny Flashcards
what do phylogenies show
history of descent with branches
patterns of relatedness among species to mke predictions about historical pattern of evolution
aim of phygoeny
give a hypothesis about the evolutionary history of the species
represent the best model or explination
what is LUCA
last universal common ancestory
suggests all organisms descended from a LUCA
attempt to make a tree for all species, tree of life
what is a clade/monphyletic group?
group consisting of an ancesotry and all of its descendents
show the evolutionary path a group has made
in humans and monkeys what are a clade
chimps and bonobos are a clade
humans, chimps and bonobos are clades
how can two species be closest relatives
if they share a common ancesotry not shared by any other species or groups of species
what is a sister group?
groups more closely related to each other than either of them are to other groups
what indicates shared ancestory
nodes
branch points
what is key about nodes
they can be rotated without changing the evolutionary relationships within the groups
define topology
trees being the same despite being drawn differently and looking different
what is synapmorphy
posession of two or more characteristics of organisms inherited exclusively from their common ancesotors
typically shares exclusivey by descendants
define homogous
indivivuals that have characterics similar because of descent from a common ancesor
define analogous
similarities due to independent adaptations by different species
what is used to build trees
morphological characterisics
but more modern trees use amino acids and DNA
define objectve way
data for three is aligned in a matrix
molecular data used and more than one genes
define clustering algrothms
keep picking the two most similar taxa untill you have a tree
old fashioned but intuative
what is the optimality criterion
decide which tree is best and use this
what is parisomy
tree explained with the frewest mutations
maximum likihood
given how many mutations happen, which tree is the best
bayseian method
search for the tre most likely to be correct
super computer used to search a database of all tree space to find the best one
what does an unrooted tree show?
informaiton about relationship but no direction of the evolution
have to root it to know this
what is an outgrou
an odd one one
used to be sure which is more distantly related to outr taxa to identify the root
where the outgroup connects is where the roor should be
convergent evolution
independnt origin of similar traits in separate lineages
