Biology 1001A Lecture Notes - Lecture 9: Species Problem, Reproductive Isolation, Speciation
Document Summary
Chapter 18 roadmap: speciation: process of species formation. 18. 1a the morphological species concept is a practical way to identify species: morphological species concept: individuals of a species share traits that distinguish them from others species, does not help distinguish closely related species. 18. 1c the phylogenetic species concept focuses on evolutionary history: phylogenetic species concept: group whose members are descended from a common ancestor, applies to , extinct species. Living organisms that reproduce asexually: only works on few organisms, few details on evolutionary history for some groups. 18. 2b postzygotic isolating mechanisms reduce the success of hybrid individuals: hybrid inviability: offspring do not complete development, dies young, hybrid sterility: offspring cannot produce gametes, hybrid breakdown: offspring have reduced survival or fertility. 18. 3 the geography of speciation: allopatric speciation: geographical barriers prevent gene flow between populations, sympatric speciation: species from in the home range without a physical barrier, parapatric speciation: neighboring populations become different species in a common border.
