Chapter 4 Flashcards
naming and classifying organisms
Taxonomy- humans have a desire to name things
evolutionary history
Phylogeny -
- Aristotle’s concept of the scale of nature
- Organisms were placed on this scale based on their proposed complexity
- Held until Renaissance when we began to discover more species
- Needed more complex system
Scala Naturae
Sentences or paragraphs (in Latin) that described an organism
polynomials , this eventually got cumbersome and turned into binomials
genus and species
binomail
Introduced in Species Plantarum (1753)
Carolous Linnaeus
- Still largely used (although modified) today - Linnean Classification Scheme
- Start from bottom - the species.
Carolous Linnaeus
- primary type - name bearer
Holotype
- primary type of opposite sex of holotype
•Allotype
secondary types, one will replace holotype if lost. Generally all specimens other than the holotype examined by the original author are paratypes unless otherwise specified.
•Paratype
a series of primary types when none has been designated as a holotype
Syntypes/cotypes
a specimen removed from a syntype series to be the equivalent of a holotype
Lectotype
the remaining syntypes after a lectotype has been designated
Paralectotype
primary type designated if primary type(s) lost
Neotype
- a duplicate of the holotype in plants
Isotype
a specimen from the same locality as the primary type(s); not officially recognized
Topotype
- Groups of interbreeding natural populations that are reproductively isolated from other such groups
Biological Species Concept (BSC)
the smallest aggregation of (sexual) populations or (asexual) lineages diagnosable by a unique combination of character states.
Phylogenetic Species Concept (PSC), Wheeler and Platnick version
an entity composed of organisms that maintains its identity from other such entities through time and over space and that has its own independent evolutionary fate and historical tendencies.
Evolutionary Species Concept (ESC)
Get rid of ranks entirely and seeks to eventually get rid of the binomialSuggests that the movement of species between genera, genera among families, etc., sets up an unstable taxonomy.
phylocode
- Short sequences of rapidly diverging genes could be species specific
- 5’region of cytochrome c oxidase subunit I (COI) - particularly promising tool for species identification
- Eventually have gene chips • Put tissue on it and a machine will tell you specie
species barcode
Evolutionary history
•Coined by Ernst Haeckel
phylogeny
– a group consisting of all descendents of the group’s most recent common ancestor
Monophyletic
graphical representation of a monophyletic group
Clade
– taxon or taxa related to group of interest (reptiles)
• Outgroup
three plus branches from node
polytomy
only 2 branches per node
Dichotomous –
-group consisting of the group’s most recent common ancestor, but not all descendents
Paraphyletic group
-group consisting of two or more groups, but not the group’s most recent common ancestor nor all of its descendents
Polyphyletic group
no branch lengths
Cladogram
branch lengths indicating some sort of evolutionary change – sequence divergence
Phylogram
Can relate to time scale when examining fossils or molecular clocks
Chronogram
Correspondence in function or position between organs of dissimilar evolutionary origin or structure
Analogy
Correspondence in evolutionary origin
Homology
derived characteristic
Apomorphy -
- primitive characteristic
• Plesiomorphy
- shared derived characteristic
• Synapomorphy
- shared primitive characteristic
• Symplesiomorphy
Assessing Homology- three requirements
- similarity
- conjuction
- congruence
PATTERSON
