Replies

There are simple, non-obligate colonials today. Volvox. Slime molds. They can live separately or form colonies. They can survive disassembly. Even sponges can do that. Where are you imagining the difficulty?

Heck, you started life as a unicellular. Then you were a simple colony of related cells. Then your cells started to differentiate ...

You cannot use the adaptivity of a multi-cellular organism, or the growth of a complex organism from the egg and sperm that already have the DNA coding to grow into a complex organism to explain how a single-celled organism creates an advantage by accidently sticking to its neighbor.

The slimes and sponges are multi-cellular creatures that can survive being split. They then reproduce, essentially repairing the damage from being torn apart. They also already have the DNA coding to perform this function. This is not the same as transitioning from a single cell, mutating, joining to another cell, and then realizing some advantage that makes this pair more resiliant than the single celled predecessors.

Post 182, however, does not beg the question in providing an answer. It deserves some follow-up.

I'm ok with the alternate hypothesis that the cell did not stick to a neighbor, but instead split into two cells that stuck together. Eliminates one of the two random factors that were required with my scenario. From many - one has some good points, providing a mechanism to provide a chain of cells. We do need to inspect the claim that the chain of cells absorbs nutrition more efficiently, but he's got a good start. We should postpone the light-sensitive part for a later mutation, however. This chain needs to survive, and thrive to get there.

No. Some of the slime molds in particular demonstrate an ability to live as individual unicellulars for arbitrarily long times. Slime molds. My point is that there's practically every degree of multicellularity out there now. So where am I supposed to imagine the hurdle?

I really don't like arguments of the "Nobody can make me understand how this happens" form. You just don't prove anything this way.

Sorry, I wasn't clear about the better survival.

Unspoken premise was a nutrient rich environment. Thus two cells have a better chance than one of mopping up the local food. It wouldn't have to be much better, just enough so that the two cells have an advantage that outweighs the burden of their greater mass.

One bit of hubris that keeps slipping in is the idea that somehow more complex is better (making us the top of the heap).

Remember, my imaginary chains did not replace the mono-cell critters, they just grew along side them and survived.

As for the eye-spot I posited...that's an oversimplification anyway. Since it was an imaginary sequence, I picked something that would lead in the direction of forming a head, as well as the frying in the sun scenario I presented.

I have a serious love of teaching, with a particular interest in presenting science for non-scientists. I get way more aha! reactions from non-science students "getting it" than ever happens when I'm an ambulatory textbook for grad students. :-)

If you tell me what your biology background is and/or ask other specific questions, I'll be more than happy to answer.