BI111 Lecture Notes - Lecture 18: Marchantiophyta, Tracheid, Root System
Document Summary
Twin goals of systemaics: reconstrucion of evoluionary history and classiicaion of species. Phylogeneic trees come about through successive events of speciaion (branching, in which one species gives rise or two (or more) Reconstrucing these trees requires comparison of traits (with shared geneic ancestry) in muliple species: (homologies are good, analogies are not) Binary nomenclature: genus and species (relect the nested hierarchy of life) Many are based on traits (sharing of common ancestors) Taxon designaion has 3 components: name: what group does it belong to, rank: where does it it into the phylogeny, content: relevant to species concept. Homologies: resemblance due to recent common ancestor: example: whale dolphin. Homoplasies: resemblance due to similar selecive pressures to ill niche: example: whale shark and ichtyosaur. Homologous structures relect underlying geneic similariies: example: bones that support wings of bats, birds and pterosaur all look like modiicaions of pentadactyl limb (5 ingered limb, develop from comparable embryonic structures.
