intro: phylogeny, classification Flashcards
define etymology
the study of word origins
taxonomy = a
biological taxonomy = b
biological systematics - c
a- system of names for categories
b - practice of classifying organisms
c - theory of classifying organisms
nomenclature
system of rules for naming things
linnaeus - naming system
binomial system.
genus & specific epithet
domain, kingdom, phylum, subphylum class, order, family, genus, species
taxon
taxonomic ranks
actual name/category that organism fits into
hierarchically nested
type
individual specimen. species - genus upon which the next higher entity is based
linnaeus - concept of species?
static concept of species.
- later, species may arise from hybridization (for plants)
darwin
phylogenesis. tree concept. more shared morphological feature = more common ancestor
haeckel’s trees
used real taxa - bifurcational tree.
goals in systematics
create taxonomies that reflect phylogenies
* not static science* - author in brackets if sepcies they discovered has since moved.
hennig and systematic
- ad authoritatum?
logical and repeatable. no longer ad authotitatum “because i said so”
synapomorphies
shared derived features
parsimony
how cladograms are decided. simplest wins.
4 main points to hennig’s cladistics
- dichotomous branches
- synapomorphies only evidence for common ancestry
- competing cladograms decided on parsimony
- taxonomy logically consistent w inferred pattern of historical relationships
ingroup
relationships youre looking at
outgroup
taxa known to have split off prior to taxa.
root the tree
- 3 things you can do to tree
rotate around branch points
prune - remove taxa but keep other relationships the same
collapse - put taxa with various branches into 1 big branch.
synapomorphies
shared, derived traits in more than 1 group
*important for reconstructing phylogenetic tree
symplesiomorphies
shared, ancestral traits
autapomorphies
derived traits present in only one taxon
princple of parsimony
best choice is simplest one
homologous
character states present in moer than one taxon and that arose once in common ancestor of that taxon
reversals
reversal from derived to ancestral state
homoplasious
states present in more than one taxon + arose independently mroe than once.
convergence
evolve independently toward similar state
divergence
evolve independently to become less similar
radiation
various species from 1 (darwins finches)
parallel evolution
closely related taxa achieve similar evolutionary modifications.
goal of cladistic reconstruction
maximize homology, minimize homoplasy, and most parsimonious
monophyletic
clades, contain all descendants of common ancestor and no others
paraphyletic
missing one or more descendants
polyphyletic
included are species that do not share a most recent common ancestor.
3 domains
bacteria
archaea
eukarya: protists, plantae, fungi, animalia.