Chapter 17: The Tree of Life

Section One: The Linnaean System of Classification Taxonomy The science of naming and classifying organisms Developed by Carolus Linnaeus Taxon: a group of organisms in the same classification system Involves binomial nomenclature Binomial nomenclature: a system that gives each species a two part scientific name using Latin Gives a genus (first name) and a species name (second name) Genus: includes one or more physically similar species that are thought to be closely related Ex: Homo sapiens

Section One: The Linnaean System of Classification Taxonomy Has 7 levels of classification Each level gets more exclusive Kingdom Phylum Class Order Family Genus Species

Section Two: Classification Based on Evolutionary Relationships Cladistics Classification based on common ancestry Phylogeny: the evolutionary history for a group of species Cladogram: an evolutionary tree that proposes how species may be related to each other through common ancestors Derived characters: traits that differ in structure or function from that found in the ancestral line for a group of species

Section Two: Classification Based on Evolutionary Relationships Species Relatedness DNA sequencing can reveal whether or not two species are related This has led to some species named being changed since they were first compared only by physical characteristic and not if their DNA was similar

Section Four: Domains and Kingdoms Tree of Life A model that shows the most current understandings of how living things are related There are currently 6 kingdoms and 3 domains The 3 domains are Bacteria Archae Eukarya

Section Four: Domains and Kingdoms Bacteria Single celled prokaryotes One of the largest groups of organisms on Earth

Section Four: Domains and Kingdoms Archae Single celled prokaryotes But have different cell walls than bacteria Can live in extreme environments like deeps sea vent and the mouths of volcanoes

Section Four: Domains and Kingdoms Eukarya All organisms with eukaryotic cells Have a nucleus and organelles Can be single or multicellular Includes the kingdoms Protista, Plantae, Fungi, and Animalia