BIOL 1104 Lecture Notes - Lecture 17: Reproductive Isolation, Speciation, Gene Flow
Document Summary
Natural selection is one way we can end up having speciation. Darwin focuses on natural selection but not really on speciation. Speciation refers to the origin of new species. Biologists compare morphology, physiology, biochemistry, and dna sequences when grouping organisms. Ex: great tree frogs, there are 2 species of frogs that look physically identical but are different species because they cant even interbreed together. The biological species concept is based on the potential to interbreed rather than on physical similarity. A biological species is a group whose members have the potential. If 2 ppl can"t produce offspring then their evolutionary independent (good def but not perfect) If you cut off gene flow, you may end up with reproductive isolation over time. They will lose the ability to exchange gametes. Gene flow between populations holds a species together genetically. Reproductive isolation is the existence of biological factors (barriers) that impede two species from producing viable, fertile offspring.