In the gradual speciation<span> model, species diverge slowly over time in small steps while in the punctuated equilibrium model, a new species diverges rapidly from the parent species. The two key influencing factors on the change in </span>speciation rate<span>are the environmental conditions and the population size.</span>
A cell membrane does not actually maintain homeostasis by itself. The term homeostasis refers to maintaining a relatively stable internal environment inside of a multi-cell organism. Since the internal environment is the interstitial fluid that is around each and every cell, then homeostasis has more to do with what is outside of a cell than what is inside of it. :)
