What is the Linnaean System of Taxonomy?

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What is the Linnaean System of Taxonomy?

• Levels of taxonomy Kingdom, Phylum (or
  Division) Class Order Family Genus and
  Species
• Today, all levels are intended to reflect
  evolutionary relatedness
• Developed by Carolus Linnaeus (mid 1700s), a
  Swedish botanist
• Binomial Nomenclature (Linnaeus, 1758)
• Each species receives a unique scientific name in
  Latin (common names differ by location and
  change over time)
• Latin is a dead language (will not change), and
  is used internationally
• Scientific names always two words (Genus
  species), always underlined or italicized
  (versus longer description in Latin) second name
  not used alone, lower case, often describes
  location species found or in honor of person
• Tomato (pre-Linnaeus) Solanum caule inermi
  herbaceo, foliis pinnatis incises
• Descriptions of Newly Discovered Species
• Often identified based on their physical
  structure (Morphological Species Concept)
  taxonomists attempt to include genetic
  comparisons and ecological descriptions also
  (e.g., habitat)
• Holotype and Paratypes first known specimen and
  subsequent specimens described in peer-reviewed
  scientific journal

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Figure 26.3
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How are Phylogenetic Relationships Determined?

• Clade an ancestral species and all of its
  descendents (a branch on the Tree of Life)
• Cladistics systematic analysis of clades and
  their relationships to other clades focuses on
  the evolutionary innovations that define branch
  points in evolution (synapomorphies shared,
  derived traits)
• Parsimony convergence considered more rare than
  homology tree that results in fewest number of
  steps considered most parsimonious
• Techniques
• Often heavy computer memory requirements for
  statistical tests (bootstrapping, Monte Carlo
  simulations, tests of monophyly)
• If multiple trees result with equal significance,
  relationships remain unresolved (a bush or
  polytomy)
• Any single resulting tree still considered a
  hypothesis best if consistent with other
  independent evidence (e.g., the fossil record)
• Character states entered for multiple traits (ex.
  horns present 1, horns absent 0) taxa that
  share more homologies considered more closely
  related nucleotide or amino acid sequences often
  used (eliminates potential bias in choice of
  characters)

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Figure 26.5
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Figures 26.2 and 26.4
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Figure 26.10
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Figure 26.11
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Figures 26.16 and 26.17
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Figure 26.6
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The Evolution of Inflation in Pufferfishes
Phylogenetic trees can be produced via DNA
comparisons (relatively free from subjective
choices of characters). Behaviors of interest
then mapped onto tree.
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Figure 26.21
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Figures 26.22 and 26.23