theme 5ab Flashcards
what is taxonomy?
the science of identifying, naming, and classifying new species
what is binomial nomenclature?
a system in which species are given a two part Latinized name, where the first part identifies and genus and the second part identifies the specific epithet (species name)
what are all the groupings in the taxinomical hierarchy?
domain kingdom phylum class order family genus species
what is a taxon?
all the organisms within any category at any level of the taxinomical hierarchy (ex: all organisms within the class Mammalia are one taxon, and all organisms within the genus Ursus are a different taxon)
what is a phylogeny?
the evolutionary history of an organism/organisms
what is a phylogenetic tree?
branching diagrams that illustrate phylogenies. are formal hypotheses that identify likely relationships among species and higher taxonomic groups
what does the root of a phylogenetic tree represent?
the common ancestor of all the species represented in the tree
what is anagenesis?
pattern of evolution as gradual change
what is cladogenesis?
when one species undergoes speciation, producing two species distinct from each other and their common ancestor
do anagenesis and cladogensis increase biodiversity?
anagenesis does not but cladogenesis does
what are sister clades?
two clades that originate from the same node
what are sister species?
two species that emerge from the same node near the very top of the tree
what does it mean when more than two branches originate from a single node?
it indicates the biologists are not yet sure what the exact order and relationship of the branches is yet, these nodes are “unresolved”
what is a monophyletic taxon/lineage?
basically a clade. a portion of a tree that consists of an ancestral species and all of its descendants.
what is a polyphyletic taxon/lineage?
a taxa that includes organisms from different clades of a phylogenetic tree but not the common ancestor of the clades
what is a paraphyletic taxon/lineage?
a taxa that includes a common ancestor and some but NOT ALL descendants
what is homology? (homologous characters; homologies)
similarity due to shared ancestors
what is convergent evolution?
the evolution of similar adaptations in distantly related organisms that occupy similar environments
what is homoplasy? (homoplastic characters; homoplasies)
phenotypic variation that evolved separately, often a product of convergent evolution
what is analogy? (analogous characters; analogies)
homoplastic characters that serve similar functions in different species
what is traditional systematics?
building phylogenetic trees by focusing on the ends of the branches: assessing amount of phenotypic divergence between lineages, as well as patterns of branching evolution that produced them. focusing on the products of anagenesis and cladogenesis
what is cladistics?
an approach that produces phylogenetic hypotheses and classifications that reflect only the branching pattern of evolution and entirely ignores phological diversion by grouping together organisms that shared derived character states
what are character states?
character states are the forms (of which there are at least two) that can a character can exist in
what is an ancestral character state?
the character state of ancestors of a clade
what is an derived character state?
the character state of the descendants of a clade that developed from ancestral character state
what is an apomorphy?
a derived character state
what is a synapomorphy?
derived character state found in two or more species
what are synapomorphies useful for?
they can serve as markers for monophyletic lineages
what is outgroup comparison?
the technique of identifying ancestral and derived character states by comparing the ingroup (clade understudy) to those of an outgroup (species that are related to the ingroup but not part of it). characters in outgroup are ancestral and those only in ingroup are derived
what is the PhyloCode?
a strictly phylogenetic system of classification of organisms
what is the principle of parsimony?
the simplest plausible explanation of any phenomenon is the best (assume complex evolutionary change is an unlikely event–most likely tree is the one w the fewest homoplasies (independent origins of character states))
what is a phylogram?
a phylogenetic tree where branch lengths represent the amount of inferred evolutionary change/time
what is a cladogram?
a phylogenetic tree where all branches are the same length
what is macroevolution?
evolution above the species level
what is adaptive radiation?
the rapid evolution of new species occupying new niches
