This has big implications for the Fermi Paradox:
<a href="https://en.wikipedia.org/wiki/Fermi_paradox" rel="nofollow">https://en.wikipedia.org/wiki/Fermi_paradox</a><p>In particular, the jump from unicellular to multicellular life is (was) one of the top leading candidates for the Great Filter.
<a href="https://en.wikipedia.org/wiki/Great_Filter" rel="nofollow">https://en.wikipedia.org/wiki/Great_Filter</a><p>Importantly, it was one of the filter candidates "behind" us. It will be exciting to see if other potential filter steps can be so conclusively eliminated over time.
Do these cells already have the blueprints for multicellular organization, latent until selection exerts pressure for its manifestation? Is it much easier to reproduce the phenomenona since it's already happened before? Do cells ever go back to the single life?
I actually wrote a program which showed behavior that appeared to be "social" after predictors were added to the simulation.<p>The postulation being organisms have a pressure (from predators) to form groups and eventually societies. Essentially, they'd either survive by evolving to be social, evolve defense mechanisms or die out. Social evolution may actually be the shortest path for non-aggressive species because they simply have to bare one another, as opposed to evolve long claws or something.<p>Very hard to prove, but our model showed given the options social interactions appeared more likely with basic reward circuitry.
So the paper says that filter-feeding predators might have been the reason, if you are bigger than a certain size you become irrelevant to them. But how does the filter predator become so big without multicellularity? I mean: filter predators always have to be bigger than their food, no? So isn't it rather coevolution?
Perhaps I'm missing something, but it seems they artificially selected for single-celled organisms that are sticky and clump together (thus making them -- as a group -- too large to be eaten.)<p>As the 'stickiness' doesn't really pose a disadvantage to the single-celled organism, the trait persists even after the predator is removed.<p>In short, can a collection of 'stickier-than-normal' single-celled organisms truly be referred to as a multicellular organism? Aren't they stretching the definition of multicellular? Each of the units, after all, reproduces on its own and there is no differentiation.
Not biologist, but I wonder whether these model organisms are valid. One might expect that today's single cell organisms may have had multicellular ancestors, but have kept the--I struggle for the word--the required genetic machinery for multicellular form in dormant/unexpressed fashion, but otherwise relatively intact and ready for expression given certain evolutiinary presures.
This would be in contrast to the original evolution of multicellular life.
Edit: I see others here have expressed this idea already, and more elegantly.
Great that I could just read all that info without jumping through hoops or just getting the abstract.<p>Interesting that the changes were then stable over many generations once the predator was removed.