例句與造句

1. :" In contrast, the second mode, sympatric speciation, is species divergence without geographic isolation, and its identification is typically controversial, since even a small amount of gene flow may be sufficient to homogenize a potentially diverging species . [ 137 ] [ 138 ] Generally, models of sympatric speciation in animals require the evolution of stable polymorphisms associated with non-random assortative mating, in order for reproductive isolation to evolve . [ 139 ] However, a common mechanism of sympatric speciation in plants appears to the the formation of polyploid species and can involve either a single plant doubling its numbers of chromosomes ( an autopolyploid such as cabbage ), [ 140 ] or two related plants cross-breeding to form an allopolyploid such as wheat . [ 141 ] [ 142 ]"
2. It's difficult to find stable polymorphism in a sentence. 用stable polymorphism造句挺難的