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Cladistics. Determining relatedness and forming theories. What it is….What it isn’t. Evolutionary systematics Organisms most related to an ancestor will more closely resemble that ancestor. Traditional form of systematics Phylogenetic systematics ( cladisitics )
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Cladistics Determining relatedness and forming theories
What it is….What it isn’t • Evolutionary systematics • Organisms most related to an ancestor will more closely resemble that ancestor. • Traditional form of systematics • Phylogenetic systematics (cladisitics) • Focus more on homologies (evolutionarily connected and shared structures) • Cladistics argues that it is more scientific and less subjective than evolutionary systematics.
Cladograms • Used to show theoretical evolutionary relationships between living (extant) and extinct species. • Phylogenetic systematics (cladistics) • Focuses on homologous structural evolution • Shared ancestral characteristics • Humans are more closely related to all vertebrate species than they are related to invertebrate species
Cladograms Take a minute right now and look at these images. Write down in your notebooks 3 separate definitions to describe how these are different.
Exit Ticket • Explain the difference between a monophyletic, polyphyletic and paraphyletic grouping. Use a diagram to help if you need to. • What is a clade? • How is evolutionary systematics different from phylogenetic or cladistic systematics?