lecture 2- evolution and shti Flashcards
biological taxonomy
theory and practice of classifying organisms
biological systematics
theory and practice of classifying organisms
nomenclature
system of rules for naming things
what book did mr linnaeus write and what did it argue
systema naturae
argued for binomial system for species w genus and specific epithet
when do valid names for animals start
1758(when systema naturae for animals was out)w
what did the early linnaean system propose
nested categories or ranks
ie kingdom class, order, genus, specific epithet(species)
the taxonomic ranks
hierarchially nested,
,domain, kingdom, phylum, subphylum, class, order, family, genus, species
taxon/ taxa
groups that have been given names
how is the scientific name written
-genus and species are italicized
-taxon names capitalized(except species)
-author of species description sometimes beside the species name
ICZN
international code for zoological nomenclature
-ie the rules for naming
what happens when taxa is higher than superfamily
ICZN doesnt control, may be more than one name for taxa
what happens when taxa lower than super family
names controlled by ICZN
one official name for taxa at each rank
extant
still alive
extinct
no longer any living members
what happens after potentially new species compared to similars and found to be new?
taxonomists describe and publish its description into scientific journal
what does describing a new species involve?
taking measurements and making drawings and taking photos, noting differences b/w new guy and already described mfs
what is a type
individual specimen- holotype
or individual species or genus upon which the next higher entity is based
ie H acanthocharis is type species of heatherella which is the type genus of heatherellidae
what is the family level taxa suffix
idae
what is the superfamily level suffix
oidea
what did linnaeus suggest about the origin of spcies
species in a genus arise after the creation of the world through hybridization
charles darwin’s idea of phylogenesis
phylogenic relationships could be portrayed in a tree like formal
significance of Haeckel
first to use real taxa rather than hypothetical for his trees
what is the goal of taxonomy and systematics
create taxonomies that as closely as possible reflect phylogenic relationships
what happens to the name of the author when a species moved to diff genus
parentheses around author and date
Willi Hennig approach
where is it used most
what is it called
approached to phylogenetics that what logical and repeatable
non molecular data2
AKA cladistics
what was the phylogenic system like before hennig?
ad authoritarian
“im the expert so these are the features used for systematics”
the main points of cladistics (4)
1) taxa relationshoips follow dichotomously branching patterns displayed on diagrams called cladograms
2) synapomorphies provide only evidence for recentness of common ancestry
3) choice bw mfsdecided on parsimony
4) taxonomy should be based on phylogeny, and phylogenic rlshps should be recontructable based on taxonomy
outgroup
taxa known or suspected to have split off prior to diversification of taxa of interest
ingroup
-taxa whose rlshps you wish to untangle
-diversified through character states
what does 1 and 0 mean in a compile list
0- state shown by outgroup
1- different state from that shown by outgroup
what are outgroup states assumbed to be
what about ingroup states
ancestral
derived
what is a polarized state change
evolutionary direction 0 —> 1
whats the difference b/w rooted and unrooted trees and what makes a tree rooted
unrooted: directionality and evolutionary changes unclear
rooted: direction of evolutionary changes clear
what makes it rooted: outgroups
clade
group that contains all descendants of a common ancestor, no others
what happens if a clade is named
it is also a taxon
do named clades have to be given ranks
no
synapomorphies
shared derived traits present in more than one ingroup taxon
symplesionmorphies
shared, ancestral traits
autamorphies
derived traits present in one taxon
what do hash markes indicate on a tree
characters hypothesized to have changed state
william of ockham- whatd he do
argued the cpinciple of parsimony, or occams razor
-most parsimonious(least amt of steps) is the best one
homologous character states
more than one species, and that arose in the common ancestor of that group
homoplasious states
present in more than one species but arose independently more than once
-convergent or parallel evolution
reversal
type of homoplasy
-reversal from a derived to an ancestral state
convergence
two or more lineages evolve independently towards similar state
divergence
two or more lineages evolve independently to become less similar
radiations
multiplle divergences from a common ancestor resulting in >2 descendant lineages
parallel evolution
two or more species of closely related taxa achieve similar evolutionary modifications
what is the goal of cladistic reconstruction
homology is maximized and homoplasy (including reversals) are minimized
-will be the most parsimonious
sister clades
two clades that share a more recent common ancestor
consensus tree
summarizes agreements as resolved dichotomous branches, disagreements as polytomies
monophyletic taxa
named clades that contain all descendants of a common ancestor
paraphyletic
missing one or more descendants
polyphyletic
include species that do not share a most recent common ancestor
phylogenies and classification are not immutable truths, they are
hypotheses to be tested
what is molecular phylogenic revolution
conflicts between molecular and non molecular datasets
some classifications are changed after additional analyses to support the new interpretation
the 3 domains
eukarya, bacteria, archaea
