Landmass Size
For development of an advanced civilization on a super water world, I think it would have to be a water world where the landmasses are not miniscule. Tiny scattered islands would not give much evolutionary chances, or pressures, for life to leave the ocean (there would be but one ocean on a water world). What benefit would there be? There would not be enough territory for land creatures to have a go at it. There may be creatures that learn to live in the shallows, and there would probably be more shallow areas than areas above the ocean surface; and those creatures may venture at times on the land. Maybe some would evolve to use the land to lay eggs - protection from egg eaters. Some plant life that survive on the surface of the ocean could also end up being OK on the tiny islands - being small land masses, on a very large water world would mean waves, storms, rain, as well as a humid atmosphere (we suspect super Earths would have thick atmospheres, and may be steamy or humid). This atmosphere would potentially offer more protection from ultra violet radiation than our atmosphere, making it easier for surface water plants to survive periods on the land masses.
But for larger land masses - large enough to support evolution of land creatures - that is a different tale. Large land masses allow room for life to evolve permanent settlers, for a complex enough, and large enough, ecosystem to allow for permanent land adaptation. Once life evolves species to permanent adapt to land, they can then spread to smaller, relatively nearby, landmasses.
Landmass Separations
On a super Earth, even large land masses, close to Earth continents in size, would be separated by vast stretches of water - a vastness that would make our oceans seem like large lakes by comparison.
On Earth, landmasses separated for long periods show us divergent evolutionary paths. Each continent on a super Earth water world would have little biological communication with each other, at least for creatures that become fully established as land creatures. Semi-aquatic could eventually find their way to other landmasses, but those that evolve to be on land - each landmass would be a separate evolutionary laboratory.
An AsideEvolutionary Laboratories
I have to stop for a moment here. While the evidence for evolution is overwhelming, it still has its holes, and thus it needs refining. But I also think that the Grand Designer of the universe has created the marvelous, awe inspiring, supremely elegant and beautiful natural laws that brought the universe to life. It's a sonnet, controlled by some regulations and restrictions, but allowing for so much expression within. For me, evolution is not anti-spiritual, but is evidence of a grand design, a remarkable design, that allows for such an incredible range of life in this universe. Many, many different songs of life, a Universe Symphony. And so, as science uncovers more truths of the universe, we will learn more of this Grand Design, and discover more of the beauty, the genius, the elegance of the Universe. This outlook informs my speculations. See "Introduction" for more on this blog's focus.
While the landmass lifeforms will have evolved from the same one ocean, the greatly separated major landmasses would allow for different evolutionary paths. Convergent evolution, where organisms not closely related (not monophyletic) independently evolve similar traits, would come into play, of course: lifeforms evolving similar adaptations because the occupy similar niches such as climbing trees, hunting at night, and eating burrowing insectoids. They would be on the same planet, within that planet's gravity well, magnetic field, and living through the planet's seasons as it orbits its star. But there will be variations in how each landmass' lifeforms specifically adapt. Natural disasters may affect one landmass while another is barely even touched by it - for instance, a supervolcano exploding on one landmass, but as the planet is a super Earth, and the landmasses greatly separated, the devastating effects of a supervolcano on this super Earth would not have the same global impact as a supervolcano explosion on Earth would. A meteor strike on a super water world would have less of a global impact, for the same size meteor, as that strike would on the Earth. A tsunami from an ocean strike would have much further to go, on a world with higher gravity, dissipating more of the tsunami's energy by the time it strikes a landmass than it would on the Earth. Not that there still would not be global effects from major disasters, it is just that with vast distances between at least some of the landmasses the effects for some areas of the planet would be much reduced. This would allow for very different end results.
Dinosaurs Kingdoms and Mammal Kingdoms?
If the Earth was a super water world, where it had, say, the same overall landmasses but with much, much greater distances between some of them due to the vastness of the global ocean, one result is that one continent would still have dinosaurs evolving, while another continent would have the dinosaurs wiped out, and the mammals evolving. Would this result in a sentient warm-blooded dinosaur race (probably feathered) on one continent, and sentient warm-blooded furry mammal race on another continent - intelligent descendants of the dinosaurs ruling one continent while intelligent humans ruling another? If the dinosaurs were not wiped out, could they have continued evolving, surviving the changing Earth to become sentient? Birds are the descendants of dinosaurs. Some birds, like crows, have brains twice the size needed for control of their bodies - they are much smarter than the other birds. Some even make tools (Caledonia crows can take a twig, strip it, and then work it until it has a hook at one end so that it can use it to hook insects burrowed in holes). If the dinosaurs were not wiped out by natural disaster(s) (some think more than one disaster ended their reign), could some have evolved to human level intelligence?
What a world that would be. One day, an explorer from the dinosaur kingdom coming across the human kingdom, or vice versa.
Exploration
Which leads to my next speculation for this long post. For a world where continents are separated by distances many times what our continents are separated by, what would that mean for exploration? A sentient being is probably a curious one, and with a need to do some exploring, expanding territory.
But as we see from our past, a large ocean is perilous to traverse. Many of our ancestors still did - we are finding that they traveled more, and farther, than we first thought. But it was perilous, and many resisted. For a continent that had only a few islands nearby and then nothing else, many early ships would leave to either never return or to return with no sightings of land. This would hold true for centuries as their sailing technology would not be enough to cover the incredible distances needed to get to another continent. The pressure to develop this technology would not be great - there is just no evidence for them, no tales of far off countries - just the known boundaries of their continent, the small islands off the coast, and that is it. The known world. The center of the world, and of the universe, as known to them.
This separation, this loneliness, would allow the separated sentient beings on the separated continents to progress on their own, focusing on their known world, their center of the world. Until one day at least one progresses to the point where they can begin to think of exploring the universe. As knowledge increases, as they being to realize their world is a giant sphere, they may again wonder if some continent lies far, far away, just like we use to wonder if sentient life existed on Mars, or the Moon. Scientific exploration leads to technology that finally enables them to send a probe around the planet, or a long range probe to cross the seas (though a planet orbiting probe is the much more efficient means), and they spot it - another continent.
Contact
And now the final speculations for this long post What myriad of ways that could play out? A civilization more advanced but for some reason didn't launch an orbiting probe (their culture focused more inward for whatever reasons - political, theological, or distracted by a more harsh environment and needing to spend more energies there). Or a civilization less advanced. People similar in body form, but still different enough: humanoid but with tails, or humanoid but much smaller. Or more aggressive. Or not humanoid at all. The first contact hidden by the government of the country that sent the probe because of the differences - delaying actual contact. Or used by the government to rally their dissafected people against a perceived enemy? Or this other land thought of as being heaven, or hell, or .... So very many different ways that first contact could play out.
(a full review is forthcoming), Dr. Shostak, in his brief mention of panspermia as one possible way life originated on Earth, brings up an interesting point about panspermia:
, Volume Two, edited by George Mann).
