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Systematics. Systematics. Classifying organisms Hierarchical organization Alternative classifications systems Phylogenetic taxonomy Analogy vs. homology Phylogenetic approaches Evolutionary systematics Cladistics Determining degree of relationship by molecular similarity
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Systematics Classifying organisms Hierarchical organization Alternative classifications systems Phylogenetic taxonomy Analogy vs. homology Phylogenetic approaches Evolutionary systematics Cladistics Determining degree of relationship by molecular similarity Characteristics used in microbial classification The three domains, overview of diversity
Major Ideas Species are classified together because they share a common ancestor. Ideally, taxa should be monophyletic. Evolutionary systematics uses degree of divergence; cladistics uses shared derived characters. Molecular comparisons have revolutionized taxonomy.
Cladistic Assumptions Derived characters originate only once. Derived characters never revert to the ancestral state. In other words, evolution is perfectly parsimonious. But…homoplasy happens.
Major Ideas Species are classified together because they share a common ancestor. Ideally, taxa should be monophyletic. Evolutionary systematics uses degree of divergence; cladistics uses shared derived characters. Molecular comparisons have revolutionized taxonomy.