BI111 Chapter Notes - Chapter 71: Meiosis, Gamete, Sympatric Speciation
Document Summary
Geography plays role in evolution of new species. Organisms subject to differential selection pressures & genetic drift = reproductive isolation & speciation. Sympatric speciation: speciation from single ancestor living in same geographic region (rare) Occurs in cases in which pop of species potentially in contact w/ another, occurring in same general area; habitats overlap & i(cid:374)d (cid:272)ould freely (cid:373)ate, (cid:271)ut do(cid:374)"t. Requires reproductive barriers such as assortative mating habitat differentiation: sympatric speciation scheme in which mutations in pop allow ind to exploit diff conditions w/in same envio. Allopatric speciation: pop of species physically isolated from one another by geographical changes. Polyploidy: organism has more than two full sets (diploid, 2n) of chromosomes. Achieve reproductive isolation leading to speciation is through this. Polyploid offspring have unique phenotypic characteristic that distinguish them from diploid pop & do not usually produce offspring w/ diploid relative. Sympatric speciation arises from two types of polyploidy:
