BIOL 201 Lecture Notes - Lecture 9: Species Problem, Allopatric Speciation, Winter Moth
26 Feb 2018
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What is a species: morphospecies concept, phylogenetic species concept, biological species concept. Morphospecies: it can lead to some problems, species are named based on morphological similarities and differences. Phylogenetic: species are established as monophyletic groups and must contain all of the known descendants of a single common ancestor. Biological: the criterion for defining a biological species is a reproductive isolation, if populations do not hybridize or make sterile hybrids, then they belong to a separate species. Problem of bacteria: present suggestion is that bacterial species are the result of lateral gene transfer and should be defined as such. Bacterial horizontal transfer of genetic material causes some problems with these schemes. Isolation (prevention of gene flow: trait divergence, reproductive isolation. Isolation: physical isolation or allopatric speciation, misc; Occurs through polyploidy in which an offspring or group of offsprings will be produced with twice the normal number of chromosomes. This prevents them from mating with left handed forms.
