Chapter 38: Q38.2-3CC. (page 834)
Self-fertilization, or selfing, seems to have obvious disadvantages as a reproductive 鈥渟trategy鈥 in nature, and it has even been called an 鈥渆volutionary dead end.鈥 So it is surprising that about 20% of angiosperm species primarily rely on selfing. Suggest a reason why selfing might be advantageous and yet still be an evolutionary dead end.
Short Answer
Pollen delivery may be uncertain in populations that are scattered and sparse, so selfing may be advantageous. In the long term, selfing or self-fertilization is an evolutionary dead end because it reduces genetic variability, limiting adaptive evolution.