There is no evidence that complex multicellular organisms evolved from single celled microorganisms.

There is no evidence that complex multicellular organisms evolved from single celled microorganisms.

http://www.creationists.org/patrickyoung/ohiosciencestds05.html

The idea that multicellular organisms evolved from single celled microorganisms is based on a hypothesis that involves an endosymbiont relationship (a cell that lives within a host cell). The endosymbiont proposal in effect, attempts to explain the existence of multicellular organisms by suggesting that all eukaryotic cells (cells with membrane-enclosed nuclei and membrane-enclosed organelles) evolved from prokaryotic cells (cells without membrane-enclosed nuclei or membrane-enclosed organelles) via symbiotic associations.

Evolutionists will attempt to justify the endosymbiotic origin of eukaryotic cells by pointing to the existence of endosymbiotic relationships in nature today. They also point out that similarities between chloroplasts and mitochondria should be considered as a supporting evolutionary foundation for endosymbiotic theory. However, the existence of endosymbiotic biological relationships in the world today does not demonstrate that eukaryotic cells evolved from prokaryotic cells. Furthermore similarity does not prove common origin. It is actually evidence for an intelligent designer.

While endosymbiotic theory is an interesting illusion, there is no evidence it ever happened to create multicellular organisms. There has also been no lab experiment demonstrating that an endosymbiont relationship can provide the required mechanistic pathway for the evolution of eukaryotic cells from prokaryotic cells. If evolutionists want to spout diatribes about the scientific method, then lets require them to stand by their own musings.

From Simple To Complex

http://www.the-scientist.com/?articles.view/articleNo/30827/title/From-Simple-To-Complex/

The switch from single-celled organisms to ones made up of many cells has evolved independently more than two dozen times. What can this transition teach us about the origin of complex organisms such as animals and plants?



http://www.genetics-gsa.org/chlamydomonas/2014/abstracts/fulltext/f145210127.htm

The evolution of multicellularity is a major evolutionary transition, occurring at least twenty five independent times across eukaryotic lineages. However, the ecological pressures that stimulate this transition are poorly understood.  Interestingly, G. pectorale, a colonial multicellular relative of C. reinhardtii does not respond to predation by aggregation, suggesting that the aggregation response may be genetically permanent in this species. Here we will report the characterization of the signal that is responsible for this aggregation response. In summary, our data indicates that predation may have driven the evolution of multicellularity in the volvocine algae.