BIO153H5 Lecture Notes - Polyphyly, Pterosaur, Ichthyosaur
Document Summary
Topics: species concepts taxonomy & the linnean system introduction to phylogenetic analysis: types of characters; types of groups. The species is the fundamental unit in classifying the diversity of life. Criteria for recognition of species: common descent (must trace ancestry to a common ancestral population, smallest distinct grouping, reproductive isolation from other organisms* Reproductive isolation is defined as occupation of a particular ecological niche so that the population responds as a unit to evolutionary processes such as selection and drift. There have been many attempts to provide a species definition that works for all types of organisms; this is still an unresolved issue in modern biology. Modern biologists tend to use the phylogenetic species concept the irreducible (basal) grouping of organisms diagnosably distinct from other such groupings and within which there is a parental pattern of ancestry and descent. This approach focuses on reconstructing the historical pattern of evolution by tracing descent relationships.
