BSCI 106 Chapter Notes - Chapter 17: Meiosis, Allopatric Speciation, Infertility

• School: University of Maryland
• Department: Biological Sciences Program
• Course: BSCI 106
• Professor: Marcia Shofner

Document Summary

There is no definition that applies in all cases. Says that all members have the potential to interbreed under and natural conditions and produce viable fertile offspring. Some hybridization is okay as long as it doesn"t occur naturally enough to overwhelm the boundary. Can be difficult to apply, not always clear who has the potential to interbreed. Phylogenetic looks at smallest group on a tree. Blue footed boobies: mechanical isolation: don"t have compatible sex organs, gametic isolation: gametes (egg and sperm) come into contact, but no fertilization takes place. Postzygotic barriers: reduced hybrid viability: hybrid offspring do not develop, or do not survive as well, hybrid infertility, hybrid breakdown: 1st generation are fertile but when they mate the 2nd generation are sterile or weak. Populations become different due to founder effect at outset and natural selection. Adaptive radiation: evolution of many diversely adapted species from a common ancestor, population from main land going to several different islands and evolving differently.