Systematics Flashcards
Systematics
Scientific study of biological diversity and its evolutionary history
-catalogue names of all life
-discover relationships
-classify species hierarchically
Taxonomy
Study of classifications, naming, and identifying
-naming and classifying organisms
-coinded by de candolle
Carolus Linnaeus
Goal was to name and classify all plants, animals and minerals
-origin of biological nomenclature
-binomial nomenclature
Parts of binomial nomenclature
-Genus (capitalized)
-species (not capitalized)
-may have authors last name at end
UNDERLINED OR ITALICIZED
ICBN
International Code of botanical nomenclature
-provide rules and recommendations for plant nomenclature
-rules are required, recommendations strongly suggested
-name new taxa
-revise old taxa
Taxon
A particular group of organisms assigned to a categorical rank
Anthophyta
Phylum of flowering plants
Var
Variety of a species (variation of phenotype)
Basionym
Like a synonym
Base from which name originated
Type specimens
-the application of botanical names is determined by means of nomenclature types
-usually a herbarium species
-comparison of other specimens in determining whether they are of the same species
Taxonomic ranks (main)
Kingdom
Phylum
Class
Order
Family
Genus
Species
Natural classification
Ultimate goal: reveal causes of diversity
-evolutionary history
-evolutionary processes
Phylogeny
-evolutionary history or pattern of descent of a group of organisms
Ideally a classification should reflect phylogeny (taxa should be monophyletic)
Phylogenic tree
-deposition of genealogical relationships between taxa
-hypothesis (proposed by a particular investigator or group of them)
Phylogenetically
Elucidation of the patterns of descent of a group of organisms
-evolutionary history and relationships among taxa
Phonetic phylogenetic analysis
Traditional
-intuitive consideration of large number of factors/ traits
-sequence of branching events
-based on investigators opinion largely
Cladistics
-focuses on branching between lineages
-identification of monophyletic groups = Clades
-clades defined by shared, derived character states
-comparison with out groups
-produces cladograms: graphical representation of working hypothesis
Monophyletic group
A common ancestor and all and only all descendants of the common ancestor
Also known as a Clade
Characters used in phylogenetic reconstruction
-morphological
-anatomical
-psyiological
-molecule
Paraphyletic group
A group consisting of a common ancestor but not all descendants of that common ancestor
Polyphyletic group
A group consisting of the descendants of two or more common ancestors.
-do not have a single recent common ancestor that is part of the group
Principle of parsimony
Of two or more competing hypotheses equally plausible, the simplest one is preferred
Ex: cladogram with fewest number of steps is best representation of evolutionary history
-minimizes number of ad hoc hypotheses
Homology
Similar due to common ancestry
Other causes of similarly between species are called
Homoplasy
Homoplasy types
Convergence: independent evolution of a similar feature in 2 or more groups
Reversal: loss of a derived feature with re-establishment of an ancestral feature
Are features homologous if they are called the same name?
No-terminology is bias
Anemophylous
Pollinated by wind
