Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
22 Cards in this Set
- Front
- Back
phylogenetic tree |
shows relationships |
|
genealogy |
whos related to whom and where did it come from |
|
phenetic vs phylogenetic tree |
phenetic= superficial similarities phylogenetic = reflect evolutionary relationships depict where things came from not how they look like today |
|
monophyletic group |
same ancestor and all its decendents defined by inclusion |
|
paraphyletic group |
common ancestor but not all descendents defined by exclusion. Made to map out ways of making a living rather than ancestry, Not very good |
|
polyphyletic group |
no most common recent ancestor but different groups s |
|
sister groups |
species or taxa that are eachothers closet relatives. are always monophyletic |
|
how do we build phylogenetic trees |
we build trees using characters, |
|
characters |
each character provides a hypothesis of relationship, molecular, morphological |
|
plesiomorphic |
primitive type of character tree |
|
apomorphic |
derived type of character for tree |
|
autoapomorphy |
really defines species. this is a type of character only seen in this clade/ taxa. sets it apart |
|
rooted versus unrooted: tree |
rooted= follows temporal path unrooted= does not follow temporal path |
|
Parsimony: tree |
based on Occam's Razor, always pick the shortest tree minimum number of evolutionary changes cons: this may be wrong hypothesis not based on biology |
|
neighbor joining: tree |
takes a sequence matrix, uses distances among genes or taxa to build tree |
|
maximum likelihood: tree modern way |
takes a set of molecular data, only, hypothesis : give computer model of how likely sequences of genes are going to change . use model of change, make multiple topologies Makes multiple trees, with a percentage of how likely it fits based on the your model.95 100 |
|
fossil record: divergence time |
is a minimum estimate of time because it is incomplete. not everything becomes a fossil. even fossil may have evolved earlier. |
|
molecular time |
genetic distance between 2 species is a function of time past. will accumulate more mutations as time since divergence happened |
|
genetic distance |
% sequence divergence between taxa, calibrated by fossil records |
|
evolutionary rates / clock |
NOT constant. different genes evolve at different rates. poor calibration = wrong rates |
|
missing branches problem |
missing taxon from tree. may have not been sampled yet, extinct, the age of each taxon/ species is anchored to its sister. each node is anchored by two species, may make the node appear older than it is. gives older ages |
|
biforcating versus budding phylogeny |
biforcating= internal branches |