Phylogeny and Systematics

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• Phylogeny and Systematics
• Cladistics
• Analysis of phylogenetic relationships based on
  shared characters
• Characters may be primitive or derived
• Clade Group of species that includes ancestral
  species and all descendents
• Cladogram Diagram that illustrates evolutionary
  relationships among clades
• Outgroup Used to distinguish primitive from
  derived characters

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• Phylogeny and Systematics
• Relationships among Taxa
• Taxa may be categorized according to how they
  reflect evolutionary relationships

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Fig. 26.10
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• Phylogeny and Systematics
• Traits in Classification
• Establishing relationships among taxa requires
  careful examination of characters
• Ancestral characters plesiomorphies
• Shared ancestral characters (symplesiomorphies)
  unite descendants of a single ancestor into a
  monophyletic clade
• Ex Vertebral column in vertebrates
• Derived characters apomorphies
• Shared derived characters (synapomorphies)
  unite derived clades and separate them from
  ancestral clades
• Ex Amniote egg and feathers in reptiles/birds
  and birds

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Fig. 26.11
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• Ecology
• Ecology from Greek Oikos (house)
• Interactions among groups of organisms and
  between organisms and physical environment
• Includes abiotic and biotic components

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Fig. 52.17
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• Physiological
• Behavioral
• Evolutionary

Fig. 52.2