Systematics and Phylogeny

• The theory and practice of delimiting kinds of organisms and classifying them

  TAXONOMY
• kinds (“species”) of organisms are recognized and delimited

  Microtaxonomy
• kinds of organisms are classified, that is, arranged in form of classification

  Macrotaxonomy
• who are the 4 founders of evolutionary taxonomy aka new synthesis

  Dobzhansky

  Mayr

  Simpson

  Wright
• other word for new synthesis

  Evolutionary Taxonomy
• during 1970s to 1980s, ano nangyari?

  Cladistics Wars
• evolutionary taxonomy led its downfall due to

  imprecise

  authoritarian

  unable to articulate a specific goal other than ill-defines naturalness
• Descended from a single common ancestors

  Monophyletic
• All descendants of a common ancestors

  Paraphyletic/Holophyly
• all systematist today are called

  Hennigan cladists
• Basis of systematic analysis

  CHARACTERS
• characters can be used for

  comparison

  intrinsic

  heritable
• why should characters be intrinsic

  naturally passed down
• characters are the primary step of establishing homology
• chracterized by Morphology, Behavior, and Biochemistry

  intrinsic
• Population size, Geographic location, or Environmental conditions

  extrinsic
• Intrinsic features are the more frequent sources of systematic information.
• is the most obviously appropriate source of comparative variation

  Genotypic
• clearly more similar in parents and offspring than they are to other creatures

  Phenotypic
• Developmental stages


  ontogeny
• Features / “Traits”


  Tokogeny
• movement of genetic information across different species

  horizontal gene transfer
• Across taxa (Evolutionary history and Vertical , gene transfer)


  Phylogeny
• Collections of organisms

  TAXA
• heck

  m

  A) htus

  B) otus

  
• Central objects of systematic analysis

  GRAPHS, TREES, NETWORKS
• nested sister-group relationship

  Cladograms
• endowed with explanation in terms of evolution, ecology, or other biological or geological factors of the changes

  Scenario
• series of ancestors–descendants statements

  Trees
• trees can be rooted or

  unrooted
• more closely related to every other taxon in the group than to any taxon that is classified outside the group

  Monophyletic
• all descendants of a common ancestor

  Monophyletic
• groups are those based on symplesiomorphy (shared primitive features)

  Paraphyletic
• Functional, convergent similarity is mistaken for similarity based on descent

  Polyphyletic
• A gene tree that models a genealogy of a gene.

  PHYLOGENETIC TREE
• branch lengths, which represent the estimated amount of genetic or evolutionary change that has occurred over time
• represent the number of character changes

  Branch lengths
• points where the different taxon deviate / speciate

  Nodes
• basal taxon / farthest relative

  Outgroup
• group of organisms with a common ancestors

  Clade