Imagining The Evolution Of Real Alien Life
May 4, 2010 7 Comments
This is not to say that intelligence could not arise from plants or fungi– just that the development period for such would seem to be far longer than that already postulated for sealife in general, and so intelligence of too high a plant or fungi content would virtually always lose the survival competition on a given world to more robust and mobile animal forms, under most imaginable conditions.
There’s also the issue of gamma ray bursters to contend with. In the history of our galaxy thus far, the far greater development time required for intelligence to arise in plants or fungi as compared to animals would seem to simply prohibit such exotic forms from getting anywhere near the status of a civilization– for they’d be repeatedly zapped back to square one by gamma bursters.
There’s evidence that evolution (on Earth) has tried varying vision systems, ranging from complete blindness to something near to three eyes in some species at one point.However, binocular, or two eyed vision, seems to have prevailed across the board in all those species of comparable size and capacities to man. So we might reasonably expect the same thing to occur on many other planets too. In the area of visual light and motion sensitivity, here too nature has experimented, with the result being our own narrow bandwidth of radiation detection (the visible spectrum), and precise, predatory sensitivity to movement. This fact provides some justification for us to expect something similar in whatever alien race we meet. However, in this there could easily come about significant differences in development from relatively small differences in environment. For example, on Earth we’ve discovered…..
The shark has a sensory net finely tuned to the detection of electro-magnetic fields that we humans either utterly lack, or possess in such small amounts as to be negligible. Dolphins and other animals exhibit extraordinary range in their hearing, and dogs superb sensitivity to smell. Cat eyes are far more sensitive to light than our own, allowing them to see better in much lower light conditions than we can.
Note that cetaceans (dolphins, whales) and even large fish predators like sharks and cephalopods like squid and , due to acoustic or other sensory apparatus being more easily adapted for similar purposes underwater. That is, their eyes are located on the sides of their head rather than facing forward, in an arrangement we mostly see on land in prey animals like rabbits.
Of course, the majority of these alternative senses and defenses are essentially merely improved or heavily modified versions of our own; not radical departures from our own feature set. This means we are unlikely to meet up with any biological entities equipped with natural senses or defenses which we cannot understand, detect, or artificially compensate for with our own devices.
Dolphins and some whales may use sonic stun beams to kill or incapacitate fish they wish to eat, as well as fight off enemies at times. Sound defenses are well suited to water environments, and much more cost effective in terms of sea based evolution, than they are in thin air. There are compelling evidences which has proven Whales to be even much intelligent.
Aside from the need for free time to exploit certain physical attributes, there is also the matter of spare energy. Intelligence seems unlikely to evolve in some forms not because of extremes in size, lack of time, or manipulative limbs free of mobility responsibilities, but rather for reasons of excessive energy expenditure or low density nutritional values in available food. Just as small size can dictate too much time is spent eating, intensive energy usage, low energy yielding diets, or an inefficient bodily design for energy use (too large or small an outer surface area related to volume, adversely affecting heat conservation or dissipation) can too. The metabolisms of birds and bats, for instance, demand almost continuous eating, although few species of these creatures reach a size comparable to man. In the reverse instance, too large a body size might impair intelligence development in other ways, by diminishing the flexibility and speed with which an animal may respond to changes in its environment.
Another important aspect of energy expenditure is how it may interfere with the advanced development of manipulative limbs and related brain regions, even if adequate time is available for such development. For example, take a very large bat with intelligence potential. It could fulfill many of the requirements for becoming sentient, but its high energy mode of mobility would stop it in its tracks. How? Let’s assume a large bat with highly developed hind paws it may use as hands. As the bat’s primary mobility is accomplished by flapping its forelegs, the highly developed hind legs are free to progress to full scale hands. But this is unlikely, as simply maintaining a position to use these proto hands is energy expensive for the bat (because it must be supporting itself in the air via flying to use its hind claws in any complex or lengthy fashion). Ergo, advanced development of manipulative organs (and the supporting brain functions) beyond a certain point is prohibitively expensive for the alien bat, and probably won’t occur.
What about monkeys and gorillas? They span a range of sizes from not much bigger than a mouse to sometimes larger than a man, and some enjoy not only analogs of hands and feet, but a prehensile tail as well– or potentially three manipulatory limbs rather than merely two. What about these non-human primates? It can be argued that this line did give rise to an intelligent star faring race– or is on the verge of doing so. Indeed, there was apparently a surplus of potential in that line; for although only one dominant race– homo sapiens– resulted from that diverse and well equipped family, there’s much evidence that there were perhaps dozens of intelligent or near intelligent branches which sprang from this group, with the resulting competition killing off all but one (us), and/or forcing a merging of the DNA into essentially a single superior strain through natural cross-breeding and sexual domination.
As for our poorer cousins who were left behind– the monkeys and gorillas– why didn’t they too evolve further along? Possibly they didn’t evolve any further because they didn’t have to. By always retreating from the waves of evolving, murderous, and aggressive ancestors of humans over millions of years, they avoided the necessity of changing, while our own ancestors were caught up in the middle of the conflict, forced to evolve or die.
So what about species which evolve under significantly different circumstances from that of Earth? Wouldn’t that throw all our assumptions out the window? Not really. Look around. Our own solar system provides examples of significantly different environments from Earth and their results. And that result is effectively zip, so far as complex, large, and intelligent life is concerned. Some bacteria or fungi or very simple plant and animal life may exist in such places, but little else.
Make the planet a bit hotter, and you diminish the land diversity while possibly increasing sea diversity (cetaceans and marine mollusks again). Make the planet a bit colder, and you diminish diversity both on land and in the sea. And the less diversity, the less chance for a star faring race to arise. Or you will increase the chance for evolution of intellient life.