Expeditious Evolution

From the very beginnings of life on Planet Earth to today, evolution has gradually brought about change and adaptation. As environmental conditions have altered, bringing about new climates, life forms have soon followed suit—the luckier variations altering to thrive in the new situation, while the less fortunate ones died out. This elegant process has caused relentless and progressive adaptation on the part of plants and animals—with the result that, at any given moment in time, the mix of living species is fairly well balanced.

There have been, however, numerous occasions when the environment changed so dramatically and rapidly that many species could not adapt quickly enough, so they became extinct. There have been half a dozen or so catastrophic events that caused some 70-95% of plant and animal species to disappear, but life soon adjusted and began to flourish again, as new species came into existence.

We are now in the midst of the latest major environmental change. It is being designated as the Anthropocene Age transformation—whereby the planet is rapidly heating. This change is being brought about by humans. And the rate is hundreds and thousands of times faster than in any comparable change in the past! That faster pace will likely see the extinction of far more species than in the past.

And yet there is already evidence that some animals are currently altering their physiology, in attempts to adapt to the warmer conditions. Some of these critters have slowly evolved (over millions of years) to find ways to radiate excess body heat. Birds' beaks help them cool, because their bills are not covered with insulating feathers. Similarly, some furry animals have evolved hairless ears, tails, and legs, in order to shed excess heat.

Current scientific research is showing that some bird species are adapting to hotter climates by growing larger beaks—to radiate heat better. Some mammals are growing longer ears or less hair on their legs. Some bats have had their wing size increase. This is evolution in action, and is rather heartening. But there may well be more to the story that is less heartening. Might these recent changes negatively impact other bodily needs, such as the ability to avoid predators or attract sexual partners? Might the changes be better at dissipating heat, but worse off for other needs?

Most importantly, the Anthropocene climate change is occurring at breakneck speed—over dozens of years, rather than thousands. That is too fast for some species to respond. Unable to change in time, they face the prospect of disappearing. Time will tell, as they say.

ET Inspections—Part 2

...Continuing a fanciful visit to Earth from outer-space visitors looking for signs of intelligence here...

Visit 4, 700 million years ago. Volcanoes had burst through Snowball Earth's ice crust, spewing carbon dioxide into the atmosphere, causing the planet to warm once again. (In a similar fashion, we humans are now spewing carbon dioxide into the air, causing another global warming event.) At that time, our space visitors would have encountered microbial life forms that were very primitive. Nothing larger than a few microns, and certainly not intelligent. Nothing much of interest going on here at that time.

Visit 5, 400 million years ago. This would have been tens of millions of years after what scientists call the Cambrian Explosion, when millions of multi-cell critters had evolved. Many primitive animals and plants were flourishing across Earth. They were fantastically varied and our visitors would have been amazed at it all, but still have noted no intelligent life forms. None of those creatures appeared to be likely to build a space ship, let alone a stone hammer.

Visit 6, 100 million years ago. Outer-space callers would have found a tropical planet, with huge, reptile-like creatures crawling on land and swimming in its oceans. Countless kinds of plants would be thriving everywhere. Earth was bursting with life, yet no sign of technology could be found. Even though those giant lizards ruled the planet, our guests would conclude that intelligent life (at least smart enough to make rockets) was not there, and maybe never would be. All signs pointed to the fact that Earth life had settled into a stable, unchanging mode. Little did the visitors know that, had they come calling 35 million years later, life on the planet would be struggling to survive, in the aftermath of an asteroid crash that wiped out some 80% of all species.

Visit 7, six million years ago. At this time our extraterrestrial callers would find that Earth was populated by mammals—especially an intriguing one that walked on two legs. They would note the planet was changing rapidly, oscillating from hot periods to times when glaciers covered nearly half of the globe. Although the upright hominids appeared to possess the potential for intelligence, their technology consisted only of crude chunks of stone. Would they advance? Time would tell.

Visit 8, today. Our space travelers would discover a planet seething in hominids, who occupy every corner of the globe. They'd note abundant examples of technology that have rendered the lives of the hominids convenient and comfortable. Their structures are everywhere, as proof of their capabilities. They even have made the first tentative steps to leave the planet and investigate nearby worlds.

Yet something appears to be awry. Many of the planet's life forms are no longer healthy and thriving, but are threatened by the overzealous activities of the over-populous hominids. There is evidence that, in their push to extend their technologies, they have foolishly polluted their world. Yes, our visitors would discover a relatively advanced species, but would doubt that it has sufficient intelligence to survive much longer. The ET travelers conclude that these hominids are yet too savage... they fight incessantly among themselves and are trashing their lovely planet. 

Maybe if they returned in a couple of hundred years, they would find that these dominant hominids either smartened up and got their act together, or made themselves extinct. Whatever fate might await this “intelligent” species, the visitors have faith that the planet has previously survived worse catastrophes, after which life took a new tack and once again flourished.

Long Recovery

Life forms on planet Earth have experienced some half dozen mass extinctions in the last 500 million years or so, during which up to 95% of species disappeared. Prior to each extinction event, the mixture of species had slowly settled into a stable balance, wherein each life form had found a niche that saw it interacting in cooperative ways with surrounding species—in ways that tended to perpetuate the blend. Evolution had slowed to a crawl, because the environment had stabilized and life forms had little reason to change.

Then some huge environmental upheaval occurred. An asteroid or comet crashed down, many large volcanoes erupted, noxious gases were burped up from the bowels of the seas, or the climate dramatically warmed or chilled. Many of those species that had been enjoying a long-term stable equilibrium suddenly found themselves with life’s comfortable rug yanked abruptly from under them. They had become a little too relaxed and vulnerable in their comfortable world. They couldn’t cope with the new harsh conditions and soon became extinct. Other species—some of whom had previously been scrambling for survival on the edges—found themselves better able to cope with the new environment. They adapted, survived, and thrived.

In the eons following each mass extinction, life on Earth slowly settled into a new mix of species. In fact, novel varieties of life came into existence in this aftermath, as evolution entered the fast track. Over time, life once again entered a stable period… until the next environmental catastrophe.

And the next mass extinction is currently underway. What is unique about this one is that it is not being triggered by a comet, asteroid, or volcano, but by one of Earth’s own life forms: Homo sapiens. This new dying off—designated the Holocene extinction—is being driven by human overabundance and overconsumption. We are now the force altering the biosphere.

Earth is still in the early throes of the Holocene extinction. Where it will lead and how many species will disappear is anybody’s guess. Society seems to be unable yet even to wake up and admit it is happening, so we continue to aggravate the process.

What humans understand even less is the rate at which these changes are occurring. To Mother Earth, this is the fastest mass extinction ever to transpire. While previous extinctions took thousands of years to pass, this one is speeding by increasingly faster—spanning just a few hundred years. To Homo sapiens that’s a fair passage of time. To the 3-4 billion year period of life on Earth, however, it’s an instant.

What we understand even less yet is that the recovery from the Holocene extinction will seem endless to us. In the aftermath of previous extinctions, life required millions—even tens of millions—of years recover. In contrast, we humans have been around just a few hundred thousand years. No one can begin to imagine what continued evolution will bring to Homo sapiens in a million years’ time. Once the recovery is over, it’ll be a very different planet. I wonder what the dominant species will be like then. Hopefully, one that’s smarter than humans today.