物种分类系统发育.pdf

26.1 Investigating the Tree of Life ▪ Phylogeny is the evolutionary history of a species or group of related species ▪ For example: a phylogeny shows that legless lizards and snakes evolved from different lineages of legged lizards Geckos ANCESTRAL LIZARD Snakes (with limbs) No limbs Iguanas Monitor lizards Glass lizards No limbs 26.1 Binomial Nomenclature ▪ The discipline of systematics classifies organisms and determines their evolutionary relationships ▪ In the 18th century, Carolus Linnaeus published a system of taxonomy based on resemblances ▪ Two key features of his system remain useful today: two-part names for species and hierarchical classification © 2017 Pearson Education, . 26.1 Binomial Nomenclature ▪ The two-part scientific name of a species is called a binomial ▪ The first part of the name is the genus ▪ The second part, called the specific epithet, is unique for each species within the genus ▪ The first letter of the genus is capitalized, and the entire species name is italicized ▪ Both parts together name the species © 2017 Pearson Education, . 26.1 Hierarchical Classification ▪ Linnaeus introduced a system for grou species in reasingly lusive categories ▪ The taxonomic groups from broad to narrow are , kingdom, phylum, class, order, family, genus, and species ▪ A taxonomic unit at any level of hierarchy is called a taxon © 2017 Pearson Education, . Species: