Changes

;How did multi-cellular life originate?

;How did multi-cellular life originate?

:Unicellular organisms can band together for mutual support and protection.  Those organisms can engage in sacrificial behavior that is for the good of the entire group.  Then, this relationship can change into a relationship where cells band together as part of an multicellular organism.

:Unicellular organisms can band together for mutual support and protection.  Those organisms can engage in sacrificial behavior that is for the good of the entire group.  Then, this relationship can change into a relationship where cells band together as part of an multicellular organism.

:In fact, during the research of my question, I discovered an article in ''PNAS'' describing an experiment in which unicellular yeasts from species ''Saccharomyces cerevisiae'' were subject to an experiment that selected on the basis of gravity, with the experimenter selecting the organisms falling to the bottom of a liquid tube.  Within 60 days, the experimenter saw the development of true multicellular yeasts.[http://www.nature.com/news/yeast-suggests-speedy-start-for-multicellular-life-1.9810#b1]

:In fact, during the research of my response to this question, I discovered an article in ''PNAS'' describing an experiment in which unicellular yeasts from species ''Saccharomyces cerevisiae'' were subject to an experiment that selected on the basis of gravity, with the experimenter selecting the organisms falling to the bottom of a liquid tube.  Within 60 days, the experimenter saw the development of true multicellular yeasts.[http://www.nature.com/news/yeast-suggests-speedy-start-for-multicellular-life-1.9810#b1]

;How did sex originate?

;How did sex originate?

:TODO

:TODO