So far as we know, all life that has ever lived on earth can be traced back to a common ancestor that emerged on the scene shortly after our island earth came into existence some 4.54 billion years ago. Estimates of when “genesis” began currently come as early as 4.41 billion years ago, a mere blink of the Gaian eye, let alone the cosmic one. From that seed sprung a sapling that grew into the tree of life we’ve struggled to chart, our evolutionary history, binding all the diverse species on the planet, through evolution by means of natural selection — or more specifically, what is known as divergent evolution. This occurs first at the scale of microevolution, which creates diversity within a species — which is to say the differences between those members give them a degree of uniqueness, but they can still reproduce with other members of the species.
These differences pile up when populations of a species become geographically isolated, however, and their uniqueness consequently grows, as in the case of the finches studied by Darwin on the Galapagos islands. He found that the finches on this chain of islands were similar to one another as well as to the finches found in America, though all the populations differed slightly from one another. His hypothesis was that the finches on each of the islands all had a common ancestor that migrated from the mainland, hence their similarities; their differences were associated with the distinct adaptations that were developed in response to their new environments on their respective islands, particularly in order to exploit the different food sources provided.
Ultimately, over the course of many generations, such populations diverge to such an extreme degree that the macroevolution milestone is achieved and speciation occurs — which is to say they become not merely a unique population within the species, but a separate species altogether. Though Tab A might still fit into Slot B for some time, it will become increasingly difficult for the two species to produce healthy offspring that are capable of reproducing themselves. It is through this process, where small modifications in response to different or changing environments add up over inconceivably long periods of time, that the first form of life on the planet led to the diverse species that have come to inhabit the globe ever since.
Divergent evolution therefore explains the differences between closely-related species — as well as the similarities, of course, given the shared history. Such similarities are known as homologous similarities, as they were inherited through a common ancestor. This explains, for instance, the similarity in skeletal structures among mammals, even whales, who bear the skeletal structures of fingers in their flippers and two nostrils in their blowholes. It explains the coccyx, or remnants of a tail, among humans. As the tree of life diverges into different species, natural selection is rather economical in that it works off of its former successes with further adaptations rather than shaking the Etch-a-Sketch and starting over, tabula rasa style. So the process of divergent evolution is rather intuitive in that way.
The same is not at all true when it comes to convergent evolution, which is a bit more counterintuitive, even mysterious, at least on the surface. This occurs when the differences between two species make perfect sense given the degree of divergence from their last common ancestor, but their remarkable similarities in traits are astounding for the very same reason. In this case, such traits are said to have an analogous similarity, as they were developed independently. This of course makes one wonder how this could happen, and the answer seems to be that natural selection favors similar solutions to the same problems.
Species that live in similar environments will develop astoundingly similar body plans, for instance, particularly if they fulfill the same role in the same niche. Dolphins, sharks and ichthyosaurs all share the same, basic body plan characterized by a streamlined body, dorsal fins, flippers and a tail fluke despite the fact that they share no common ancestor from which they could have inherited such traits from. They developed them naturally and independently because they are all marine predators and these traits are perfect for maneuvering in a fluid environment. It is for this same reason that birds, bats and butterflies all independently evolved the similar trait of wings, which are clearly successful adaptations for maneuvering in the air, and why the legless, ground-welling and subterranean creatures known as worms and snakes themselves look so similar to one another. This also occurs at the level of body organs, such as the eye, which has developed several times independently. Ears and sonar have also independently evolved more than once. So though evolution by means of natural selection is by no means teleological, which is to say it does not deliberately aim towards a single, ideal form, even specific to environments, patterns do indeed emerge — common traits do develop between organisms separated by genetics, time and space.
In light of this fact, regardless as to whether panspermia is the process that spreads life out across the universe from a single genesis or life on earth and countless exoplanets had an independent genesises, we should expect there to be commonalities between life on earth and life out there. Or, at the very least, that makes sense to some of us. Others seem to find this notion distasteful, among them astrophysicist Neil deGrasse Tyson and Dr. Jonathan Losos, a Harvard biologist. In a discussion between Tyson and and Richard Dawkins, Tyson brings up his disappointment with the humanoid body-plan of Hollywood aliens, calling it unimaginative and improbable — the same argument all too often used by those debunking the alien abduction phenomenon. Rather than agreeing with him, however, Dawkins kindly raises objections:
“Other worlds are going to be very different, but we perhaps shouldn’t write off the possibility that the Hollywood aliens… they might not be that unimaginative. I mean, my colleague Simon Conway Morris has even suggested that it’s very likely that there will be, if not humans, at least bipedal, big-brained, language-toting, hand-toting, forward-looking eyes for stereoscopy, pretty much humans. He thinks it’s highly likely. He’s got a religious agenda, I’m sorry to say, for that, but like him, I appreciate the power of natural selection.”
For anyone that became acquainted with the work of Dawkins through his outspoken atheism, it should be clear that his value in the perspective of Cambridge University paleontologist Simon Conway Morris in this particular matter had to be well-earned one. Even so, Dawkins never properly articulated the reasons behind the perspective of Morris or why, for that matter, he agreed with him, though Losos was a bit more clear in his reasoning against the general idea.
Alien life, argues Losos, may take many turns, and to support his argument he highlights what he called evolutionary singletons, which are species with what appear to be unique adaptations found nowhere else on earth. He fails to consider the possibility that his sample population is only planetary and may simply not be large enough to see how even the traits of these apparent singletons might be echoed throughout the cosmic community of life. So certainly they, like every other form of adaptation we find throughout the history of the earthen animal kingdom, exist, but so do those of the intelligent, humanoid, opposable-thumb variety. And while we seem to have the potential to eventually directly observe and interact with the variety of extrasolar life that surely exists out there is the vastness, we have yet to venture very far in our spacefaring journey, which leaves us with the question: what kind of extraterrestrial life may venture so far as to directly observe or interact with us?
There is good reason to suspect that in order for an advanced, extraterrestrial species to create a technology with which it might communicate with us or visit us it may require a humanoid body plan — or at least that it may be one of a limited number of body plans necessary to properly exploit intelligence.
Consider, for instance, the existence of an extraterrestrial species that is far older and more intelligent than the smartest human being that has ever lived, but that this intelligent mind evolved in a body akin to an octopus that is itself trapped in the depths of an ocean encapsulated by the surface ice of Europa. Despite its vast intelligence such a creature would have never seen what dry land is like, let alone the sky, and would be unable to so much as start a fire. Or consider that a creature such as a crow or an elephant that possessed such intelligence. Our earthly octopuses, crows and elephants are certainly intelligent creatures and they — and creatures of far lesser intelligence — have been seen to utilize sticks and other such things as simple tools, but how would they be capable, regardless of their intelligence, of developing high technology? Human beings were able to develop such technology due to the convergence of several necessary factors, with our intelligence being only one of them. In addition, we evolved in a manner that led to us to being bipedal, which freed up our “front legs” so that they could be used as arms, thereby enabling us to use our intelligence, via our opposable thumbs, to manipulate our environment in accordance with its desires, fashioning spears, steam engines, hydrogen bombs and spacecraft.
And what other variables might have had to have come into play, perhaps out of sheer chance, so as to enable us to develop technology sophisticated enough that we could potentially communicate with extraterrestrial intelligence (ETI) and ultimately evolve from our status as a planetary species to become a stellar, and eventually interstellar, civilization? Fermi’s Paradox may be explained by an unimaginably thick buffer betwixt the emergence of simple, planetary life and a spacefaring civilization — a buffer composed of more layers of “filters” between than we could ever hope to imagine.
Clearly, we can’t be sure. But that a species would need sufficient intelligence that naturally evolved in a humanoid body would certainly seem to be a reasonable starting point. If such a humanoid ETI became interstellar, they would surely explore various planets and study all available forms of life, though their interest would become most acutely focused on those extraterrestrial species that shared important traits with them: sisters and brothers in cosmic, convergent evolution, as it were.
If we dare to adopt as a working hypothesis that the mass of reported alien encounters and alien abduction reflect happenings in objective actuality, subjecting the appearance and behavior of the most commonly-reported aliens, known as the Grays, to analysis with convergent evolution in mind might provide us some insights. We might be able to mentally reverse-engineer the environment in which they developed and even determine what kind of species they are — or are at least akin to from the vantage point of the earthbound life with which we are familiar.
Despite sharing the humanoid body plan with human beings, after all, the Gray aliens show no signs of being mammalian. They have no nipples or breasts, nor lips for suckling. They express no emotion on their faces. They have never been seen to sweat. They have no hair. If we scrutinize them closely enough and run through the natural “escalation of hypotheses” regarding their biological nature, we may arrive at the same suspicion that many abductees tend to share — namely, that these entities are insects, or at the very least insect-like.
Insects arrived on the Gaian scene far earlier than man, his simian ancestors, or even mammals. They first appeared some 500 million years ago, having evolved from crustaceans into one of the very first land-dwelling animals. As a whole, insects tend to mature and reproduce rather rapidly, and within a single insect’s lifetime it can often produce hundreds of offspring, and though many if not most of them die before reproducing, those that do survive and reproduce carry on their successful mutations. This increased genetic diversity means a greater likelihood of favorable mutations developing — genetic “errors” that enable them to adapt to and exploit a wide range of environments. As a consequence, they have spread out across the earth, rooting themselves in nearly every conceivable terrestrial habitat, some considerably extreme from the human perspective. They also have an increased probability of successfully adapting to changing conditions within their given environments, which would not only explain how they have managed to so swiftly evolve resistances to the insecticides we develop but how they managed to survive many of the extinction events that have plagued the earth since her birth. It should therefore not be surprising at all that they presently make up three quarters of all animals on earth: there are a million known species collectively composed of some 10 quintillion individuals.
Given a different planetary and historical context and sufficient time, it is not at all that difficult to see how a species of insect might have developed the intelligence, body-plan and will necessary to emerge as the dominant species, to take the global throne.
It can’t be ignored, of course, that there are also clear differences between the Grays and what little we know regarding our own, earthbound insects — but assuming they are indeed insects, should this be all that surprising? We evolved from apes, after all, and this does not suggest that an extraterrestrial exobiologist could come to a wholesome understanding of us by means of studying the apes or apelike parallels on their own planet. We became human when we evolved the newest part of our brains and began walking upright, and this made us quite distinct from other apes. Given different conditions on a different planet in another star system and enough time, it is not at all that great a leap to assume that at least one insect species might have developed the morphology, intelligence, technology and motive necessary to bring them to our pale, blue dot, where they could interact with members of our own species.
Unlike our earthen insect species, they are not characterized by six legs and antennae, they have no body hair, and their mouth doesn’t seem to operate for the purposes of either consumption or breathing — but there may be good reasons for this. They may not have evolved the capacity to taste or smell given the nature of their particular ecosystem, or perhaps different organs developed to serve those purposes — nostril holes may have developed for olfactory purposes instead of antennae, for instance. Some have hypothesized that the insects with which we are familiar have six legs because they are so small and move so quickly, whereas larger animals move more slowly and their nervous systems are more adept at maintaining balance with four legs or less. In that light, perhaps the Grays have two legs rather than six simply because they are larger. Alternatively, or perhaps additionally, it may be due to the fact that they evolved on a planet with less gravity than the earth, which would reduce the balance issue regardless of size. Though not all earthbound insects have wings, most do, though such a low-gravity planet may have also reduced their necessity.
That they have binocular vision, which is to say that their eyes are positioned in front of their head rather than to either side, would seem to suggest they evolved from a predatory insect species. That their eyes are large and black may indicate that they need to pick up more light than we do, so they may live in an environment much darker than our own — a planet with thick cloud-cover, shorter daytime hours, that their planet resides farther from their star(s) or that their home star(s) are of a different type, that they are subterranean creatures, or perhaps only that they are a nocturnal. Alternatively, or perhaps additionally, their eyes may be so large simply because they are insects, which is to say because those eyes are compound eyes, enabling them to see a wider range of the light spectrum than we can.
These are so far only small matters in my mind, however. More broadly, my reasons for suspecting they are insects are threefold: first, they appear bear the three qualities of eusociality; second, it explains their physical form; third, it helps explain their psychology.