The Cosmic Reset

In an early episode of the original Star Trek, aliens put Kirk on a rugged planet to duel with the captain of a rival Gorn ship. Kirk wins as the dinosaur-like Gorn was intelligent but really slow.

On Earth, dinosaurs never became intelligent. Arising 240 million years ago, they survived some 175 million years and for 135 million of those were the dominant land animal. By the time they became extinct, dinosaurs had perfected two ways of living: eating plants or eating each other. The plant eaters were excellent at converting plant matter into animal bulk and could grow very large. The carnivores were very good at using tooth and claw to eat the vegetarians. Some carnivores – such as the raptors – may have hunted in pacts and perhaps had some wolf-like intelligence. But in general, brain power doesn’t seem to have been on the dinosaurs’ primary evolutionary path.

Mammals arose just 10-15 million years after the dinosaurs. But for most of their first 160 million years, they lived underfoot as squirrel-sized, nocturnal plant eaters and insectivores. For this life style, relatively larger brains gave an evolutionary advantage. So under the feet of the dinosaurs, mammals got smart. Still, even with their brains, they could not compete with tooth and claw.

Enter the six-mile wide asteroid that found the earth 66 million years ago. That asteroid – nudged out of its distant orbit by a chance encounter with another rock or after swinging too close to Jupiter or Saturn – had travelled silently on its way for perhaps a million years to arrive just seconds before the earth moved just beyond it in its own orbit. When it hit, it set the earth on fire and after it had burned away, caused a long dark winter that left most creatures dead and many extinct, including the non-avian dinosaurs. This disaster was, however, good news for the mammals. Perhaps because they were small, lived underground and could eat anything, some survived (along with birds, who are smart flying dinosaurs). Within a million years, the earth had recovered and mammals were the dominant large land animal. Some of those eventually evolved even further in reliance on brains, eventually producing us.

That asteroid wiped the slate clean, resetting the course of animal evolution in favor of the brain and intelligence. There is no reason to assume that an additional 66 million years would have led the dinosaurs towards the Gorn as in 175 million, it had not done so. It’s as if the universe has a bias in favor of intelligence and sent a “do-over” to set things right.

Dinosaurs and Intelligence

Dinosaurs arose some 240 million years ago. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201 million years ago. Their ascendancy lasted another 135 million years until the Cretaceous mass extinction 66 million years ago opened the world to the eventual rise of mammals and us. The first mammal-like forms appeared some 225 million years ago. But for the next 160 million years, mammals had to find their niches in the shadow of the dinosaurs, characteristically living a nocturnal lifestyle, emerging from burrows to feed only at night. This may have favored the evolution of better eye-sight, smell, touch and hearing to be able to navigate, find food and survive in the dark. But they still had to hide from the dinosaurs.

The question of why dinosaurs never developed cognitive intelligence, despite the many millions of years they were the top vertebrate clade, forms a rich WWW vein. (Search for the question and check it out.) Some dinosaurs did get quite intelligent in the form of birds. Some avian dinosaurs are even tool users. But there is no evidence that dinosaurs ever achieved anything like the human intelligence which has allowed us to alter our environment in ways both planned and unplanned. We human beings (the last surviving species of the homo genus) have been around for only some 200 thousand years. If one starts counting with the Australopithecus, then our progenitors go back around 3.6 million years. In either case, the fact that dinosaurs didn’t develop intelligence and complex technology even over a hundred million years while we did in just a few raises at least two questions: Is the rise of intelligence inevitable and does it have survival value over the long run?

The second question may be easier to answer. Dinosaurs and all other life on earth have done pretty well without human-style intelligence. Indeed, intelligence has not played a major role over the four billion years of life on earth. Some dinosaurs may have been clever hunters, as are wolves for example, and Jurassic Park has shown us a possible example. But they apparently found the use of claw, teeth, armor and size sufficient to last until a huge asteroid took them out with most other life. This leads to an answer to the first question, was the rise of intelligence inevitable. We can never know what might have happened with the clever dinosaurs if they were given the next 65 million years instead of mammals. Large brains need extra oxygen and are costly in energy. Maybe there would never have been any evolutionary advantage to making the investment. Human intelligence may be a cosmic accident, the result of a particular rock hitting at a particular moment allowing the burrowing underclass – mammals – to take their furtive ways into the sunlight.

So to return to the question of the long-term survival value of our big brains, the dinosaurs did really well without them and it is not clear that they will save us from ourselves.

What if non-avian dinosaurs survived?

There seems to be a growing consensus that the number of dinosaur species was already in decline before the great asteroid impact that ended the Cretaceous era 66 million years ago. As Science News reports, as of about 50 million years before the mass extinction the number of new dinosaur species was being eclipsed by the number going extinct and dinosaur diversity was decreasing. Duck-billed and Triceratops-type dinosaurs were doing well until the end of dinosaur days as was a group of small toothed raptors. But ultimately, only avian dinosaurs – the birds – survived.

Why did the number of dinosaur species decline over time and why did only avian dinosaurs survive? The dinosaur decline might have been due to climate change perhaps brought on by continental drift and the resulting land-form, rainfall and ocean current alterations from the late Jurassic onward. Perhaps only birds survived the long “nuclear-type” winter after the impact because they could eat carrion and seeds, of which there might have been much. Some small non-avian dinosaurs also could have been able to do the same but they might not have been able to travel long distances. Perhaps only a small number of birds – even just a few species – made it through on remote islands and as the earth recovered, they could spread. The land-bound non-avian dinosaur survivors – if any – might not have been able to reach places where their numbers could then rebound.

But what if there was no impact or somewhere creatures like the small raptors made it through? Carnivorous tyrannosaur- and velociraptor-type dinosaurs (theropods) were doing well at the end of the Cretaceous. Indeed, it may be that the hundred million year-plus competition between carnivores and herbivores had led to the evolution of a lesser number of species but ones ever more evenly matched. Some of the largest herbivores and carnivores ever were alive at the end. And it may have been that the carnivores were getting smarter, perhaps even hunting in packs. (The herbivores apparently had long been herd animals.) Seems the smaller theropods – like Troodon – were the (relatively) smarter ones. It is interesting to speculate how earth's evolutionary processes might have played out differently if at least some of these non-avian theropods had survived the great impact. With another 66 million years of evolutionary competition, might they have gotten even bigger brains, as primitive primates eventually did. Or perhaps I was just too impressed at an early age with the Gorn captain forced into combat with Captain Kirk.