Lab 3 - phylogenies Flashcards
taxon
named group of organisms at any level of biological hierarchy
ancestral can be also know as
derived
ancestral and derived are used to refer to the
time of the appearance certain traits in evolutionary history
when is a structure ancestral
if it is found in the earliest member of an evolutionary lineage
when is a structure derived
if it is found in later members of the lineage
a _____ trait is changed from the ancestral form
derived
ancestral or
plesiomorphic
derived or
apomorphic
shared derive characters are known as
synapomorphies
shared ancestral characters are known as
symplesiomorphies
synapomorphies are traits that
are shared by two or more groups of taxa AND that originates in their last common ancestor
symplesiomorphies
shared ancestral trait
Synapomorphy
shared derived trait
autapomorphy
derived trait that is NOT shared
a character that exists in a single taxon only is called
autapomorphy
homologous structures result from
divergent evolution
analogous structures result from
convergent evolution
sister taxa
groups that share a common ancestor AND are more related to each other than to other groups
parsimony
assumes the simplest interpretation of all available data is likely the correct explanation
principle used to decide between several hypotheses
parsimony
the most parsimonious tree is the one with
the fewest number of characters mapped on
cladistics
the method of determining evolutionary relationships by analyzing the features they share
a phylogenetic trees obtained via cladistics is termed a
cladogram
homoplasy
collective name for a series of conditions that violate the assumptions of cladistics analysis
what are examples of homoplasy
- reversals
- convergences
convergence
independent origins of a feature in unrelated lineages
reversals
a lineage has exhibited a derived character at some point in its evolutionary history BUT the character has reverted to an ancestral state
tree length is defined as the
sum of the minimum number of substitutions OVER all sites fro the given topology
Consistency Index (CI)
measures the number of times a single character changes
how to calculate CI
total number of characters used/sum of each time the character is mapped
what does a CI of 1 mean
the characters are only mapped once (NO homoplasy)
what does a CI of less than 1 mean
the characters are mapped MORE than once (homoplasy)
three types of phylogenies
- monophyletic
- polyphyletic
- paraphyletic
monophyletic
groups contain the most recent CA and ALL of the descedants
polyphyletic
- Doesn’t include most recent
the CA of all
group members - members derived from two
or more ancestral forms
paraphyletic
Contains MOST recent
common ancestor of
all group members
and SOME of its
descendants
OG
the taxon that is closely related to, but NOT part of, the ingroup (group under study)
myxini
hagfishes
petromyzontida
lampreys
Chondrichthyes
sharks, rays, skates
aquatic Osteichthyes
ray-finned fish, coelacanths, lungfish
amphibia
frogs, salamanders, toads,
reptilia
birds, turtles, lizards, snakes
Mammalia
rodents, carnivores, ungulates, primates
what taxonomic group is this
myxini
what taxonomic group is this
petromyzontida
what taxonomic group is this
aquatic Osteichthyes
what taxonomic group is this
Chondrichthyes
what taxonomic group is this
amphibia
what taxonomic group is this
reptilia
what taxonomic group is this
reptilia/birds
what taxonomic group is this
Mammalia
what trait is common to ALL vertebrates in this lab
notochord
what trait is do cephalochordate NOT have
vetebrate
what trait do myxini and petromyzontida NOT have
jaws
what trait do Chondrichthyes NOT have
bony skeleton
what trait do aquatic Osteichthye NOT have
4 limbs
what trait does amphibia not have
amniotic eggs
what trait do reptilia not have
mammary glands
what type of tree is this (1)
monophyletic
what type of tree is this (2)
paraphyletic
what type of tree is this (3)
polyphyletic
what does tree 1 represent
apomorphy
what does tree 2 represent
plesiomorphy
what does tree 3 represent
autapomorphy
what does tree 4 represent
synapomorphy
what does tree 5 represent
homoplasy