BISC 102 Lecture Notes - Lecture 12: External Fertilization, Sympatric Speciation, Meiosis
21 Apr 2016
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Morphological species concept: just like humans, there are small differences among individuals, but need to look closely. Species are discrete groups of organisms, defined by unique reliable morphological characteristics that separate them from other species. but: This is a simple concept, but some species are diverse in morphology, or cryptic (differences are not morphological). Applicable for asexual and sexual groups (all life forms) Doesn"t resolve cryptic groups (2 groups that look the same, but don"t interbreed): also called sibling species . Confounded by morphs (interbreeding populations with different phenotypes, such as geographic varieties) It is not very useful for studying speciation. Biological species concept (bsc): species or groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups. Emphasizes reproductive isolation (example: animal gene flow among species). Cannot be applied to extinct species, asexual species, or prokaryotes. Cannot be applied to fossils or asexual organisms (including all prokaryotes)
