Cycle 9 (Workshop) Flashcards
A phylogenetic tree is used to:
Show evolutionary relationships
Where can one find a MRCA on a phylogenetic tree?
Find the branching point of the two species
How do we determine how closely related two species are?
The more recent the branching points are, the more closely related
Define:
Clade
All descendants of an ancestor
Define:
Sister Clade
Clades that share a most recent common ancestor
Monophyletic means:
Includes MRCA and all the descendants
Non-monophyletic means:
Does not include MRCA/all the descendants
What is difference between ancestral and derived traits?
Ancestral traits evolved before the MRCA
Derived traits evolved before the MRCA
Define:
Autapomorphy
Derived traits unique to a single taxon
(uniquely, derived, character)
Define:
Symplesiomorphy
Ancestral trait shared 2 or more taxa
(Shared, ancestral, character)
Define:
Synapomorphy
Derived trait shared by 2 or more taxa
(Shared, derived, character)
Define:
Outgroup
Consists of species related to a clade, but not included in it
What is outgroup comparison used for?
To identify ancestral and derived traits
To identify the root (common ancestor of the ingroup and outgroup)
Determine if this trait is ancestral/derived:
Present in outgroup
Present in ingroup
Ancestral
Determine if this trait is ancestral/derived:
Present in outgroup
Present in some ingroup
Ancestral
Determine if this trait is ancestral/derived:
Not present in outgroup
Present in some ingroup
Derived
Define:
Homology
Similarity that reflects common ancestry
Define:
Convergence
Not closely related organisms develop similar features through evolution
Define:
Homoplasy
Misleading similarities or dissimilarities (trait missing/gained for separate lineages)
What is the Principle of parsimony?
A particular trait is unlikely to evolve independently in separate evolutionary lineages (simplest possible approach is the best
Most parsimonius = Least number of ____________ _______
Evolutionary changes
Goal of cladistics
Make phylogeny
How does one make a phylogeny?
Compared shared and different traits to guess which organisms are closely vs. more further related (outgroup comparison)
