Extraterrestrial Civilizations - Isaac Asimov [94]
Nevertheless, the human being is one of the four largest primates now existing, and those four are all more intelligent than the smaller primates from the gibbon downward. What’s more, Homo sapiens, the species that is the brightest of the hominids, is also the largest.
Of the nonprimate mammals the most intelligent are the elephant and the dolphin, and they are large animals, too. The octopus, which is the most intelligent of the invertebrates, is among the larger invertebrates; and the crow, which may be the most intelligent of the birds, is among the larger birds.
This very largeness must be one of the reasons for the delay in the establishment of intelligence on Earth (and, presumably, on any similar planet), since it must take considerable time for the blindchance processes of evolution to develop a species large enough to house a brain large enough for the purpose.
What makes it even more difficult is that the brain is by far the most complexly organized of all the tissues, so that it is far easier, so to speak, to develop additional mass and intricacy in any of the tissues other than the brain. Therefore, there are many more large-bodied, small-brained species than large-bodied, large-brained species.
Might not the difficulty of producing a large body with a large brain be so great as to preclude it in almost every case?
Of course, we might argue that intelligence offers such advantages that the tendency toward it would be overwhelming. After all, it is our intelligence that grants human beings security against any form of life large enough, armed enough, vicious enough to demolish us if we were not intelligent. No mighty predator can stand against us. Indeed, we must make a special effort to avoid extinguishing the proudest and most magnificent species in existence—and despite all our efforts we may fail. The power of our intelligence is too great to soften and make mild.
Let us, however, not be misled by our pride. Our intelligence is not an all-encompassing advantage. There are disadvantages, too. Since an intelligent organism must be relatively large, it must also be relatively few in numbers. It must be long lived, to take advantage of its intelligence (for if it dies before it has learned much, its intelligence goes for nothing), and it must therefore reproduce comparatively slowly.
If an intelligent species must then compete with other species, which, not being intelligent, can afford to be small, numerous, fecund, and short lived, the intelligent species labors under a serious disadvantage. There is every reason to think that evolution hands the award (survival) to the quality of fecundity more than to anything else.
The intelligent species has young that are few and that are quite helpless until the extraordinarily complex brain, which cannot reach adequate growth even during an extended stay as fetus, develops sufficiently. If something happens to the young organism before it can in turn reproduce, it represents the loss of an enormous investment of time and effort (both biological and social).
A tiny unintelligent species can produce thousands or even millions of eggs, which will quickly hatch out myriads of young that can live independently of their parents. Most will be eaten, but the investment for any one of them is negligible, and some will surely survive.
What’s more, to be short lived and fecund is to evolve at breakneck speed. The insects, which are the most familiar example of short-lived, fecund organisms, have evolved into more species than make up all noninsect organisms put together, and by any standard other than that set by our own vanity are the most successful group of organisms in the world.
Nor can humanity, at its present peak of intelligence and technology, defeat the insects. We can effortlessly destroy elephants and whales, but the insects, who consume large fractions of our food supply, defy us. We can kill them