Modern atmospheric oxygen levels average around 0.21 atm, but when multicellular life was evolving, levels of around 0.10 atm would have been the norm — too low for most multicellular organisms. "Daily fluctuations in oxygen would have made it very difficult for animals other than simple creatures like sponges to exist," explains Jim Gehling, a palaeontologist at the South Australian Museum in Adelaide.
Gingras and his colleagues propose that the mats had a key role in helping early animals to get the oxygen they needed. "We think that animals used the small but highly oxygenated zones as oases," says Murray.
But even this idea has its challenges. Night time oxygen levels would have been too low and large animals might have had difficulty accessing the oxygen in the narrow mats. Perhaps, Gingras hypothesizes, evolution solved these problems with “mat-hugging behaviours.”
This sort of unfounded speculation is typical in evolutionary theory. It brings a creative, story-telling, element into science, where unlikely scenarios with little empirical support are routinely set forth as though they are genuine scientific explanations.
And, as in this example, these just-so stories often entail substantial serendipity. In this case, the evolution of multicellular animals is made possible by the earlier evolution of particular microbial mats and special mat-hugging behaviors.
Evolution must have first produced the needed lagoons, photosynthetic bacteria, and mat structures to set the stage. Then came multicellularity that just happened to have nearby mats available. Even with all this, however, problems remained. Evolution luckily just happened to produce the much-needed mat-hugging behavior. It was sheer luck (remember, evolution has no brains), but when that behavior happened to arise, it must have been wildly successful.
This, then, is science in the hands of evolutionists—a vehicle for story-telling. Religion drives science, and it matters.