Chapter 26 - Phylogeny and the tree of life. This chapter explain the justification for taxonomy based on a PhyloCode; explain the importance of distinguishing between homology and analogy; distinguish between the following terms: monophyletic, paraphyletic, and polyphyletic groups; shared ancestral and shared derived characters; orthologous and paralogous genes; define horizontal gene transfer and explain how it complicates phylogenetic trees. | Chapter 26 Phylogeny and the Tree of Life Overview: Investigating the Tree of Life Phylogeny is the evolutionary history of a species or group of related species. The discipline of systematics classifies organisms and determines their evolutionary relationships. Systematists use fossil, molecular, and genetic data to infer evolutionary relationships. Taxonomy is the ordered division and naming of organisms. Binomial Nomenclature In the 18th century, Carolus Linnaeus published a system of taxonomy based on resemblances. The two-part scientific name: Genus species. The first letter of the genus is capitalized, and the entire species name is italicized Both parts together name the species. This is the species specific epithet. Hierarchical Classification Linnaeus introduced a system for grouping species in increasingly broad categories. The taxonomic groups from broad to narrow are domain, kingdom, phylum, class, order, family, genus, and species. A taxonomic unit at any level of hierarchy is called a taxon. Taxonomy: Hierarchical Organization: Domain Kingdom Phylum Class Order Family Genus species Species: Panthera pardus Genus: Panthera Family: Felidae Order: Carnivora Class: Mammalia Phylum: Chordata Kingdom: Animalia Archaea Domain: Eukarya Bacteria Figure Hierarchical classification Linking Classification and Phylogeny Evolutionary Relationships Systematists depict evolutionary relationships in branching phylogenetic trees. Their PhyloCode recognizes only groups that include a common ancestor and all its descendents. A phylogenetic tree represents a hypothesis about evolutionary relationships. Each branch point represents the divergence of two species. Sister taxa are groups that share an immediate common ancestor. Species Canis lupus Pantherapardus Taxidea taxus Lutra lutra Canis latrans Order Family Genus Carnivora Felidae Mustelidae Canidae Canis Lutra Taxidea Panthera Phylogenetic Trees Evolutionary Relationships Figure The connection between . | Chapter 26 Phylogeny and the Tree of Life Overview: Investigating the Tree of Life Phylogeny is the evolutionary history of a species or group of related species. The discipline of systematics classifies organisms and determines their evolutionary relationships. Systematists use fossil, molecular, and genetic data to infer evolutionary relationships. Taxonomy is the ordered division and naming of organisms. Binomial Nomenclature In the 18th century, Carolus Linnaeus published a system of taxonomy based on resemblances. The two-part scientific name: Genus species. The first letter of the genus is capitalized, and the entire species name is italicized Both parts together name the species. This is the species specific epithet. Hierarchical Classification Linnaeus introduced a system for grouping species in increasingly broad categories. The taxonomic groups from broad to narrow are domain, kingdom, phylum, class, order, family, genus, and species. A taxonomic unit at any level of .
