BIOL 1104 Lecture Notes - Lecture 18: Neanderthal, Reproductive Isolation, Ecological Niche
20 Apr 2020
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Lecture 18 morphological differences can prevent successful mating of one species may not be able to fertilize eggs of another species. Gametic isolation : if gametes are incompatible; occurs when sperm. Reduced hybrid viability or postzygotic barriers : fail to reach sexual maturity or may be infertile or be fertile but have reduced fitness and through generations go through hybrid breakdown; ex: horse and donkey= mule and mules are sterile. ****all these barriers may lead to reproductive isolation. The biological species concept cannot be applied to fossils or asexual organisms (including all prokaryotes) Only applies to sexually reprodocing species (does not apply to prokaryotes) Ex: homo neanderthalensis, evidence of neanderthal and homo sapien sexual reproduction ex: people of asian dna prob have 2% of neanderthal. Another problem with this concept: the biological species concept is difficult to apply to situations where gene flow is rare but hybrids are viable.
