Phylogeny Flashcards
What is Systematics?
reconstruction of evolutionary history and classification of species
how do phylogenetic trees come about?
through successive events of speciation in which one species gives rise to two or more
requires comparison of traits in multiple species
What is binary nomenclature?
Genus and species
what are the three taxon designations?
name-what group does to belong to
rank - where does it fit
content - relevant to species concept
what is a homologous trait?
inherited trait be a common ancestor
what is a homoplasties trait?
similarity due to selective environmental conditions
what does selection act on?
the phenotype
what is a homology structure?
development of an individual “recreates” its own evolutionary history
what are ancestral structures?
combinations of ancestral and derived characteristics in evolutionary history
what is a derived structure?
determined from fossils and embryos
appear later in development
outgroup comparison for derived characteristics
what is it called when no homologies exist?
the trait is analogous
why do analogous structures evolve?
adaptation to similar selection pressures
what is parallel evolution?
ancestors looked similar and end species look similar
start relatively the same, end relatively the same
what is convergent evolution?
species start at two different ends and finish with relatively the same
what determines the success of regulatory genes?
natural selection
what is the principle of monophly?
all groups in a clade includes a common ancestor and all of its descendants
what we want
what is the principle of parsinomy?
simplest explanation most likely to be correct due to evolutionary change being an unlikely event
what is a polyphyletic taxon?
taxon includes species from different evolutionary lineages
what is a paraphyletic taxon?
includes an ancestorial species and only some of its descendants
don’t want
what is molecular characters?
allows independent testing of evolutionary hypothesis based on fossils
what are the advantages of molecular characters?
abundant data
easier to comparison of distant or very close relations
what are the disadvantages of
only four states of nucleotides, 20 amino acids
based changes may have evolved independently
