One clue at the center is the evolution of the brain, perhaps best depicted through the encephalization quotient (EQ) postulated by Lori Marino of the SETI Institute. The EQ is simply the ratio of body mass to cranial capacity. For the dinosaurs, this ratio was far below 1.0 - since their masses were exponentially larger than their cranial cavity. In such individuals, intelligence as we understand it does not exist.
On earth, EQ has tended to increase for some species and flatline or decrease in others. Reptiles, for example, have become no more intelligent. On the other hand, mammals including both apes/hominids and cetaceans have demonstrated adaptability and increasing EQ. Marino shows that environment does not limit the advance in EQ necessary for complex behavior, since some dolphins and whales have EQ's approaching those of modern humans: 5.0 for example where humans are 7.0.
The implication is that intelligence can evolve in surpisingly different environments, though perhaps the basic building blocks do not vary much: carbon, water, complex organic molecules.
Thinking about recent developments on Enceladus, it may be that there are numerous microclimates around the universe (even in this solar system) that share common traits with certain aspects of microclimates on earth - the basic building blocks are present and a range of temperature exists enabling life and sustained reproduction. The fact that two life forms on earth are so similiar yet evolved along a different path so as to be apparently unrelated suggests that life can exist in greater profusion and proximity to earth than could have been imagined. It would seem intelligence and cognitive evolution are closely related, wherever life exists.
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