Chapter 20 Flashcards
what are systematics?
the study of evolutionary relationships
what is phylogeny?
organism’s evolutionary history and its relationships
what is a phylogenetic tree?
a visual depiction of phylogeny
is phylogeny fact?
no, it’s a hypothesis
what are the three domains?
bacteriae, archea, eukarya
what is the root in a phylogenetic tree?
ancestral lineage giving rise to all organisms on the tree
what is the branch point in a phylogenetic tree?
where two lineages diverged
what is the basal taxon in a phylogenetic tree?
lineage that evolved early and remains unbranched
what are sister taxa in a phylogenetic tree?
two lineages stem from the same branch point
what is a polytomy in a phylogenetic tree?
a branch with more than two lineages
what do phylogenies depict?
evolutionary relationships
how are phylogenetic trees structured when they are based on the presence of shared characteristics?
yes/no equals separation, with the yes branch point continuing up the tree
why is binomial nomenclature in latin?
it’s a dead, universal language that won’t change
what is the most inclusive classification?
domain
what is the most specific classification that is always present?
species
what is an even more specific classification than species but isn’t always present, and has 3 names instead of just 2?
subspecies
what are shared derived characteristics? give an example
similarity that is inherited from the MOST RECENT common ancestor of an entire group, like fur in the class mammalia
what are ancestral shared characteristics? give an example
similarity that arose PRIOR TO the common ancestor of the group, like the vertebral column in the class mammalia
what kind of characteristics are considered informative about evolutionary relationships?
shared derived characteristics
what can be classified as a character?
any part of the phenotype, like morphology, behavior, physiology, DNA
how should characters exist?
in recognizable states, like presence or absence of character
what kind of characteristic is presence of hair in mammals?
shared derived characteristic
what kind of characteristic is presence of lungs in mammals and why?
ancestral feature, it is also present in amphibians and reptiles
what happens to shared derived characteristics as you move further up a cladogram/phylogenetic tree?
they become ancestral characteristics as more branch points form and evolution takes place
what kind of characteristic is presence of teeth in mammals and reptiles?
ancestral
what kind of characteristic is absence of teeth in birds and turtles?
shared derived
what is a clade?
species that share a common ancestor as indicated by the presence of SHARED DERIVED characteristics
how are clades used when creating a phylogenetic tree?
as evolutionary units
what do clades refer to in a phylogenetic tree?
a common ancestor and all descendants
what does a clade include in a phylogenetic tree?
all descendants from a particular branch point
clades can vary in size based on what?
which branch point is referred
are clades separate units?
no, one clade can be nested in another
what is a taxon?
refers to a named taxonomic unit at any given level of classification
what is a monopyhletic group, where is it located on a phylogenetic tree, and what does it include?
synonomous with clade, from a single branch point, includes an ancestral species and ALL of its descendants
give an example of a clade?
clade amniota
what is a paraphyletic group?
consists of ancestral species and some BUT NOT ALL of its descendants
what is a polyphyletic group?
consists of a grouping of species but DOES NOT include the most recent common ancestor
are species within polyphyletic groups closely related?
not necessarily
what is an outgroup?
a species/group from an evolutionary line that is closely related to but not part of the group of interest (ingroup), like a basal taxon
what does the most parsimonious phylogenetic tree require?
the fewest evolutionary events
