How many users on these boards actually support "The Theory of Evolution"?

[hsrob]

I would like to address some flawed assumptions regarding Slimebeast's problem of why we don't have multicellular prokaryotic organisms. (Skip to the end if you don't want to read the wall of text.)

Firstly there seems to be an assumption that somehow multicellular organisms are the pinnacle of evolution and therefore prokaryotic organisms in time should, due to selective pressure evolve into this 'higher' multicellular form. The design of evolution, if we can state it this way, is survival, not specialisation, complexity or diversity per se. The fact that bacteria accounts for more of the earth's biomass than all eukaryotes suggest that perhaps their form, i.e. unicellular is in fact the superior life form in the eyes of evolution.

Secondly we are ignoring a very simple fact regarding prokaryotic cell respiration. Regardless of the huge scope of the bacterial genome it is still bound by the laws of physics. Prokaryotic cell respiration occurs in the cytoplasm and across the plasma membrane, thus it is constrained by the cells surface area to volume ratio. If cells group together, as is the case with some forms of prokaryotes which demonstrate some degree of specialisation, you are still constrained by how efficiently the external cells can respire across a limited cell surface area. Now perhaps bacteria can evolve to increase the concentration of respiratory chain proteins expressed on the cell surface but ultimately that still has it's limits. Perhaps a folded cell membrane could evolve but maybe that makes the bacteria more susceptible to other environmental pressures. If there is indeed a constraint on prokaryotic multicellularity due to simple physical principles then that in turn would account for lack of variation within prokaryotes as there is limited number of changes that could occur within such a simple individual cell that are compatible with survival. Multicellularity allows a greater degree of diversity as cells can specialise and change to a much larger degree without necessarily adversely affecting survival of the organism.

So you question evolution based on the assumption of inevitable multicellularity, which you assume imparts survival benefit, while ignoring the fundamental constraints placed on prokaryotes by their method of respiration. This is not a strong basis on which to question a theory which has held up remarkably well over 150 years.