Systematics and Phylogenies Flashcards
Why do we need a comprehensive classification system?
there are a lot of species out there. This helps us organize and helps us better understand evolutionary relationships
What is systematics?
study of evolutionary relationships
What is phylogeny?
an organism’s evolutionary history and its relationships
What is a phylogenetic tree?
visual depiction of phylogeny, which is used as a hypothesis to understand relationships
Who has the first idea of phylogeny?
Darwin
What are the two types of phylogenetic trees?
rooted and unrooted
What are the three domains?
Bacteria, Archea, and Eukarya
What is the root of a phylogenetic tree?
ancestral lineage giving rise to all organisms on the tree
What is the branch point of a phylogenetic tree?
where two lineages diverged
What is the basal taxon of a phylogenetic tree?
lineage that evolved early and remains unbranched
What is the sister taxon of a phylogenetic tree?
two lineages stem from the same branch point
What is the polytomy of a phylogenetic tree?
a branch with more than two lineages
What is another name for phylogeny?
cladogram
What is taxon?
a named taxonomic unit at any given level of classification
What do phylogenies depict?
evolutionary relationships
What are the types of taxonomy? (??)
levels of classification, binomial nomenclature, taxon (taxa plural form)
What are the levels of classification in order?
domain, kingdom, phylum, class, order, family, genus, species, subspecies
What is binomial nomenclature?
/Genus species/
What are derived characteristics?
a similarity that is inherited from the most recent common ancestor of an entire group
What are ancestral (traits)?
a similarity that arose prior to the common ancestor of the group
What is the only thing considered informative about evolutionary relationships?
derived characteristics
What characteristics can cladistics use?
any aspect of the phenotype (morphology, behavior, DNA, physiology)
What is the most reliable characteristic used for cladistics?
DNA
How should the characters exist in cladistics?
recognizable character states
What does amniote mean?
terrestrial
What is an ancestral characteristic?
is older in terms of when it emerged in that particular lineage
What is a derived characteristic?
is more recent in terms of when it emerged in that particular lineage
In terms of all animals, what kind of characteristic is hair?
derived
In terms of all animals, what kind of characteristic are lungs?
ancestral
What is a cordat(a)?
they have a nerve cord and a hard rod
In terms of all animals, what kind of characteristic is teeth?
ancestral
In terms of all animals, what kind of characteristic is absence of teeth?
derived
What is a clade?
a species or group of species that share a common ancestor as indicated by the possession of shared derived characters; a common ancestor and all descendants
What do all organisms within a clade stem from?
a single point
What is a monophyletic group?
synonymous with a clade, an ancestral species and all its descendents
What is a paraphyletic group?
consists of ancestral species and some (not all) of its descendants
What can you use to define a paraphyletic group?
things like whether they are extinct, have wings, etc
What is a polyphyletic group?
consists of a grouping of species but does not include the most recent common ancestor; species within this group may not be very closely related
What is an outgroup?
species (or group) from an evolutionary line that is closely related to but not part of the group of interest
What is the principle of parsimony?
“Occam’s razor,” shaving away unnecessary complications
The most parsimonious tree ________.
requires the fewest evolutionary events
What are shared ancestral characters?
one found in the ancestor of a group because all members of the taxon/clade have it
What are shared derived characters?
trait possessed by some members (or a certain clade) of the lineage, but not all.
