Cycle 9 Flashcards
_______ - the study of evolutionary relationships between different taxa
Phylogeny
All the species alive OR dead are represented on the endpoints?
ALIVE
A ___ could be a species, or larger/smaller, just a group of living things
taxon
We can use ______ to figure out what individuals are more closely related
phylogeny
Time flows from __ to ___
root to tips
Branching points
Lineage diverged into humans and birds
Represent _____
speciation
MRCA on the ___
Nodes
Can represent the ___ information just in tree format
same
Important thing: _____ of branching events
sequence
_____ names should reflect evolutionary relationships (all members of a named group need to be closer related to other group members than to anything outside the group)
Group
Using phylogenies in classification
Important in _____
taxonomy
___ groups: two taxa most closely related
Sister
Cladisitic method of classification: only _______ groups (clades) get names
monophyletic
Anything that includes all the descents of that group’s MRCA:
monophyletic
Many traditionally-recognized groups are not ______
Ex: prokaryotes, dicots, fish, reptiles, monkeys, protista, monera etc
monophyletic
T/F Similarities don’t always correspond to relatedness
TRUE
T/F all traits provide useful information about evolutionary relationships
F: Not all traits provide useful information about evolutionary relationships
_______ (not a useful trait in reconstructing evolutionary relationships)
Unique to a single taxon
Derived (not present in MRCA of the entire group)
Autapomorphy
_______ (not a useful trait)
Shared by two or more taxa
Ancestral (already present in the MRCA of the entire group)
Symplesiomorphy
______ (the only type of similarity to be paying attention to)
Shared, derived (present in MRCA of taxa with the trait, but not in MRCA of the entire group)
Synapormophy
Cladistics: only use ______ (shared, derived) when making phylogenies
synapomorphies
What about derived vs ancestral? How can we know what the group’s MRCA was like?
Find an outgroup… close-ish relative known to have branched off earlier than any of the groups of interest
Shared vs unique is hard or easy?
easy
The outgroup is ___ a member of the ingroup
not
The _____ would still have to be Fairly closely related to ingroup
outgroup
_____ comparison helps identify the ancestral state
Outgroup
Is it 100% accurate?
Not 100%, but probably
Is this trait probably ancestral or probably derived?
Present in outgroup and ALL in group = _______
ANCESTRAL
Present in outgroup and SOME ingroup = ______
ANCESTRAL (One evolutionary loss)
Absent in outgroup, present in SOME of ingroup = _____
DERIVED
Present in the outgroup, but NONE of the ingroup =
NOT SURE (two equally likely explanations)
Absent in outgroup, present in ALL of ingroup =
NOT SURE
Outgroup comparison relies on _____: the simplest explanation is best
parsimony
The tree requiring a ___ steps of evolutionary changes is probably correct
few
_____: similarity that reflects common ancestry
Homology
______: Similar traits developed because the environment is not common ancestry
Convergent evolution
EX of _______: wings, auditory vocal learninMolecular methods (DNA sequence) - MUTATIONS g, fingerprints, camera eye, etc
Convergent evolution
_______: misleading similarity or dissimilarity
Homoplasy
Similar traits despite not being closely related
Homoplasy
Convergent evolution
EX:
hippos and alligator
________:
Species may be closely related to each other, but just because they have different lifestyles/environments they developed unique traits
Divergent evolution
______ support the correct phylogeny; homoplasy’s are misleading
Homologies
