LIFESCI 1 Lecture Notes - Lecture 3: Paleozoic, Extinction Event, Plate Tectonics
Document Summary
Two species w/ different # of chromosomes hybridize. If chromosome # of hybrids are odd, it may reproduce asexually, but not sexually. If it then duplicates its genome, it"s back to even # of chromosomes and can now sexually reproduce, but probably not with either parent species. Just like that, it has become its own new species. Up to half of the 300,000 known species of flowering plants are thought to have originated in this way. Taxonomy (classification) + phylogenetics (evolutionary patterns) = systematics. Taxonomy: classifying organisms into hierarchical groups based on similarities. Domain, kingdom, phylum, class, order, family, genus, species. Phylogenetics: illustrating evolutionary relationships (history of speciation events) by constructing phylogenetic trees based on characteristics of extant (not extinct) taxa. Phylogeny: true evolutionary history of a group of organisms. Phylogenetic tree: hypothesis of evolutionary relationships based on one or more genetically determined traits. Currently the most commonly used class of data for building trees.
