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Carolus Linnaeus
- Developed the hierarchical classification scheme that is still used today (Linnaean system)
- Believed in special creation, so evolution was not considered when he classified organisms.
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Linnaean System
- classifications built off similarities.
- under this system, birds would be placed in their own order, because nothing else resembles them.
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Three Main Methods of Systematics
- Evolutionary Systematics
- Numerical Phenetics
- Phylogenetic Systematics
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Evolutionary Systematics
- Classification involving relatedness as well as morphological diversity (overall similarity)
- Endorsed by Ernst Mayr and George G. Simpson
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Numerical Phenetics (Numerical Taxonomy)
- Based on similarities and differences among taxa
- All characters are given equal weight (not realistic)
- Lots of characters, lots of math
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Phylogenetic Systematics
- Identifying and understanding evolutionary relationships among the many different kinds of life on earth, both living and non living\
- Relationships established by phylogenetic systematics often describe a species' evolutionary history and its phylogeny.
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Phylogenetics
The study of ancestor/descendant relationships among taxa revealing "family trees" of taxa
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Willi Hennig
- Father of phylogenetic systematics.
- Systematics should reflect the known evolutionary history of lineages as closely as possible.
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Hennig's Auxiliary Principle
Never presume convergent or parallel evolution; always presume homology
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Relative Apomorphy Rule
- (outgroup comparison)
- Homologous characters found only in the in-group are apomorphic (derived) while homologous characters shared with a sister group are plesiomorphic (basal/primitive or ancestral state)
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Grouping Rule
Only synapomorphies provide evidence of common ancestry.
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Inclusion/Exclusion Rule
Information from two transformation series can be combined into a single hypothesis of relationship if that information allows for the complete inclusion or exclusion of groups which fomred by the separate transformation series.
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Monophyletic grouping
All species share a common ancestor, and all species derived from that common ancestor are included. This is the only form of grouping accepted as valid by cladists
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Paraphyletic grouping
All species share a common ancestor, but not all species derived from that common ancestor are included
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Polyphyletic grouping
Species that do not share an immediate common ancestor are lumped together, while excluding other members that would link them.
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Cain's rule of thumb
Criteria used/aused for indicating center of origin of taxon
- 1. Location of greatest differentiation of a type (greatest number of species)
- 2.Location of dominance or greatest abundance of individuals (most successful area)
- 3.Location of synthetic or closely related forms (primitive and closely related forms)
- 4. Location of maximum size of individuals
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Panbiogeography
- Croizat
- Importance of styding multiple groups to determine biotic patterns
- Noted similar patterns of disjunction
- Drew "tracks" to indicate historical connections
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Vicariance Biogeography
- Nelson and Platnick
- Phylogeny of taxa will match the historical relationships among geographic localities if speciation resulted from vicariant events.
- This is not expected to hold if isolation resulted from jump dispersal
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Phylogenetic Biogeography
- Brundin
- importance of rigorous and objective methods in the analysis of biogeographic data
- Strongly advocated for the application of Hennigian Cladistics
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Biogeographic Histories: Hawaii
- Some show a simple progression of old island colonization and subsequent colinization of newer islands in order they emerged.
- Others reveal more complex patterns of colonization across the archipelago.
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