Collecting, comparing, discovering, naming, and describing species.
Step 1 to taxonomy
arranging species into hierachical systems by determining relationships through comparing and cladistics.
Step 2 in taxonomy
- hypothesizing historical biogeography and ecological evolution from cladistics-based patterns.
- ex: where did something come from, and where did it go
Step 3 in taxonomy
Preparing keys, manuals, and atlases for species and higher groupings.
Taxonomic know how?
- identification services
- environmental inventories at different levels
- managing and curating collections and museums
- establishing distribution patterns of species
- determining rarity and endangerment of species
What is a taxon?
grouping of related organisms recognized at some hierarchical level.
Category or rank?
simply a particular level of hierarchy.
- ex: ephemera...ephemeroidea
- -ini (fairly common)
- ex: ephemerina
-ina (convention, not rule...very rarely used)
Determining common ancestry
Step 1 using cladistics
- establish characters (like genotype and phenotype).
- this will establish what is to be the natural grouping.
Step 2 using cladistics
- Describe the variablility found among the characters
- also called character states
- ex: present or not present, just one or two
Step 3 using cladistics
- determine which of the character states is most likely the ancesteral state vs. the derived state.
- this is known as character polarity
- unique characters
- found among some portion of the study units in the study group
Step 4 using cladistics
code the characters and states and establish their distribution among already existing groups.
step 5 using cladistics
group any synapomorphies (common derived character states) together
Step 6 using cladistics
construct a family tree (cladogram) that illustrates the branching relationships
- based on cladistic derived data
- made up of only holophyletic groupings
Contains ALL progeny from an immediate common ancestor
- contains SOME, but NOT all progeny of an immediate common ancestor
- not allowed in pylogenetic classification
- Contains progeny of different immediate anscestors
- Not allowed in phylogenetic classification.