Posts Tagged ‘extinction’
There are times when the obvious slaps you in the face, like that rake you forgot in the yard — concealed in the grass, tines pointed to the sky — that you’ve just rediscovered by stepping on it in that particular way that rather rapidly accelerates the wooden handle’s rise toward your nose. “Thwack”.
What I’m thinking about today is the end of the world as we most often envision it.
In the Bible, once the human story (that God has created the earth to tell) ends, the earth ends as well, with the promise that God will make a new heaven and new earth, sort of a divine version of that song “If that Earth of mine don’t shine, I’ll burn it up and give you one that’s fine”.
And though coming from a radically different point on the ideological spectrum, the rallying cry of environmentalism has been a similarly dire one: we must change our ways in order to “save the planet!”
What these examples have in common is an underlying notion that our story as humans and that of the planet we live on are the same story. Like a jilted lover, we seem to find it unbearable to contemplate that our planet might be willing and able to go on without us!
The religious scoff at environmentalists, certain that it is human pride alone that suggests we small creatures could ever harness the power to destroy a planet that God made. But such a critique is rooted so completely in religious belief that it cannot be taken seriously as a scientific argument. (Environmentalists, for their part, at least base their predictions regarding the fate of our species on actual science).
But they are both fighting over the hand of the same object of affection: the Earth.
Because our planet is essential to our own existence, we have, perhaps, a natural need to lay claim to its affections. But the fact is that the Earth was here long before we came along, and it will be here long after we’re gone. It was no more “attached” to the dinosaurs or the trilobites as it is to us. If Earth were capable of caring about us at all, it would very likely see us as but one in a long string of short-term lovers. Yes. It turns out that Earth is a slut.
And yet our obsession is such that we can’t imagine the Earth continuing without us (at least not in any recognizable, desirable form). The religious fantasize the earth throwing itself on our funeral pyre, so to speak, having no reason to go on, whereas the environmentalist might see Earth stumbling on as a chronically-toxic dump ruined by our industrial rapaciousness, a cautionary tale to any future suitor. But to imagine Earth continuing on as a verdant, beautiful shimmering planet, spinning as ever through the cosmos? It wouldn’t dare!
This is how self-centered we are. This is how important we think we are to a vast, mindless universe. On some level, it is almost impossible for us to really accept that humanity was not the (secret) goal of evolution all along, or that God made the Earth so he could delight in our company. Either way it only stands to reason that when we come to our end so should the Earth!
But what is there in any observable reality that suggests this should be so? Nothing. We may want to believe that the universe cares about what we do, but so far all of the evidence strongly suggests that it doesn’t.
But we humans care about what we do (and how we do). And that is the only point to environmentalism that is worth anything to our self-interest: preserving and prolonging the conditions that support our existence (which naturally extends to the myriad other life forms that are a part of that web of existence). The religious are right about one thing, even if for the wrong reasons: we will never destroy Earth. Not — as they believe — because God won’t allow it, but simply because we are not up to such a monumental task. But they are wrong on the other, for altering the narrow zone of air, water and soil that support life is very much within our power, and we now appear to be well on our way to creating a set of conditions that will alter the earths’ climate in ways that will visit untold misery and destruction of millions of our fellow humans (and other life).
Discussions about the end of the world are lost in a fog of ideas and conceptions of that world. We are clearly powerless to prevent a new age of volcanism, or the eventual fiery end of Earth as it is swallowed up our Sun. Such things represent forces of a magnitude that would take no more notice of our presence than a steamroller would of a bacterium. But it could be that we might be able to use our technology to stave off the next (seemingly inevitable) large asteroid impact, or that we may be able to keep at least one train from leaving the station: the current trend of global warming and sea level rise.
But the argument is further muddied by the unacknowledged self-centeredness of the human psyche, in our insistence that life revolves around us, even to the extent of thinking that an entire planet will just die if we leave it. On some level this makes sense. After all, we are the animals that bring meaning to biology. Not by being the actual purpose of biology, but by dint of having evolved into conscience beings that are able to contemplate such things. And since we are the only animals in the meaning game, it makes some sense that we would project our conclusions about significance on the blank screen of the meaningless universe. But just because we can imagine our world in this way, does not make the world of our imagination real.
(I reviewed a book that was the notable exception to the idea of a shared fate between earth and humanity (“The World Without Us” by Alan Weisman — reviewed this blog). This book is one long science-based thought experiment in imagining the ways that the products of human activity will decay over time. It is a rather unsentimental vision, and only for those who are ready to face the fact that earth may not shed a tear for us when we’re gone).
But by the same token, I don’t support the notion that we humans are a cancer on the planet. This view, too, smacks of a moralistic self-loathing that is unsupported by reality. We may be like locusts or any historic species whose population exploded at some time and who ate themselves out of existence. These and many more species have come and gone and the Earth itself has been no worse for the wear. The damage that we concern ourselves with has always been that which occurs in the thin veneer of biological life that coats the surface of this rocky planet. The planet itself chugs along, re-melting and re-forming crust along deep cracks in the surface, minor ecological irritants on it’s surface having no impact on it’s molten metallic heart.
And yet, having said all of that, it remains a tragic and sad picture to imagine the Earth after we are gone. Not because the Earth will miss us, but because we will no longer be here to enjoy our life upon it — because there may be no other animal evolved to a point to engage in the study a star, or experience a sunset as a beautiful thing. But that is a grieving for our own eventual departure. That is me as a social animal feeling the full brunt of being alone in a vast and mindless universe. That is a reminder that whatever meaning we bring to existence will leave with us when we go. Like a movie projected onto a blank screen, our impression on the Earth will last only as long as our movie runs. The blank screen may seem to come to life for the lovely moments we watch the movie play, but it does not become the movie itself.
To be sure, everything that is in us will return to the earth and the water and the sky and carry on as long as matter exists. But our constituent parts will never again reassemble and bring our eyes and ears and minds back to life. In this is the recognition of the terrible sadness and excruciating beauty of existence.
Let us stop expecting earth to cast itself upon our funeral pyre out of grief. Instead, let us cherish the life and love and meaning that are within our reach. For, as Robert Hazen writes in “The Story of Earth” (reviewed here this week):
“If you seek meaning and purpose in the cosmos, you will not find it in any privileged moment or place tied to human existence. The scales of space and time are too inconceivably large. But a cosmos bound by natural laws that lead inevitably, inexorably to a universe that promises the possibility of knowing itself, as scientific study inherently suggests, is a cosmos that abounds with meaning.”
Although it’s easy (and correct) to critique religious views that place humanity at the logical end of a creation timeline (whether that creation occurred in the Biblical Garden of Eden or through hundreds of millions of years of evolution), it is worth taking a step back to consider that this teleological bias infests just about every human head, be they believer or scientist.
When (as a boy) I first learned about Neandertals, they were seen (along with every other early hominid) as our direct ancestors. At that time, all different shapes and sizes of early primates and humans were just sort of crammed into a single family tree, with explanations abounding about how one evolved into the other and, eventually, to us.
Of course, it’s fair to be kind to these ideas (that are now clearly wrong), as we haven’t had all that many ancient human fossils to examine, and the technology to truly examine them scientifically has been developing rapidly over the last forty years.
As my geo-chemist friend pointed out with regards to studying the tectonic actions of Earth “We only have one data point”. Meaning that we’ve only found one planet (so far) that has the qualities of Earth to study. When it comes to our early human ancestors, we have a few more “data points” than that but, still, we don’t have all that many.
When a new fossil discovery hits the press, there is always a bold proclamation about how “everything we thought we knew” is thrown out the window, or an equally confident claim of where the fossil fits in our family tree.
But it is a testament to the steady work of science that all such announcements are eventually put through the wringer, and out the other end comes a more sober evaluation of what the new discovery can reliably tell us.
And so the sequencing of Neandertal DNA (quite a story of technology and tenacity in itself) has opened up new swaths of data from bones that we thought had already told us all that they could.
The story of the story we tell of the Neandertals is enlightening. At first thought to be our classic “caveman” ancestor, brutish and dumb, they have had a sort of re-birth as noble, red-haired, cultured savages who may have been our equals (in their time). Both of those descriptions are turning out to be a bit overdrawn, and it seems like we are settling down to an understanding that — though necessarily based on frustratingly few pieces of evidence — seems much more likely to be accurate.
For the Neanderthals now appear to be cousin to our Ice-Age “modern” human ancestors. It also appears that (though highly evolved in their own right) they may have lacked a handful of key social and cognitive traits that many think made the difference when it came down to a question of “them or us”.
More importantly, it seems to me, we are coming to appreciate them for who and what they were, without the need to either demean or ennoble them out of our own emotional needs to feel guilt or superiority (after all, there is a chance that we played an active role in killing them off about 40,000 years ago).
So what about this “cousin” relationship? Darwin predicted that it was Africa that was the nursery for modern humans, and he guessed this without a single ancient human fossil to go by. Subsequent fossil finds (and modern DNA sequencing) have so far proven him right. There are still some who hold a view that many populations of humans evolved in multiple regions on the planet, but the mainstream view now is one that we did, in fact, evolve in Africa before spreading out into the rest of the Earth.
But here’s where things have gotten interesting. As always seems to be the case, when scientists first decided that we had, in fact, all “come out of Africa”, they looked for a single migration event that led directly to us. It seems we can’t help but think that way. But the science now supports a more nuanced view that, frankly, fits much better with how nature actually works.
Our current view, then, is that there have been lots of lines of humans through the millennium, most of them evolving in Africa, and occasionally migrating out of there where some groups found long-term success (the Neanderthals in the Middle East and Europe, Homo Erectus in China before we “modern” humans arrived). There are signs in our DNA of a lot of cross-pollination between ancient humans in Africa, which makes sense when we look at other animal populations. (The fact is that we can’t tell from fossils alone whether our ancestors had spectated to a point where they could no longer exchange genes. It looks like they hadn’t, despite some surely dramatic morphological and cultural differences. And, knowing humans as we do, there can’t be much doubt that we would find a way to have sex with just about anything that looked remotely like us).
The DNA evidence also seems to confirm that there was mixing of genes between the Neanderthals and the modern humans that first migrated into their areas (there is no sign of this mixing in modern African populations, nor of modern human DNA in Neanderthals), as well as some mixing going on between modern humans and Homo Erectus in Asia.
What we begin to see is the natural ebb and flow of reproduction among related species in a way that fits with what we observe in other animals. And here is the key: it has taken us a while to really see ourselves as being “just like” the other animals. (Even in science, we held on to an idea of our specialness, even when it kept us from properly interpreting the data of our origins).
But having at long last made that intellectual leap, we can now begin to appreciate what we think we know about our evolution. The picture is complex and rather sobering. For it turns out that there have, indeed, been countless groups of human varieties since we split off from our last common ancestor with modern apes (but even then, there was much cross-breeding for a very long time!). If this is true, what happened to all of the other groups of “humans” that did not lead directly to us? The answer is that they went extinct, in groups large and small.
But not too large, for it appears that the most critical factor in the evolutionary leap that we refer to as the Neolithic Revolution may have had almost everything to do with population size.
Modern studies of hunter-gatherer populations give us a picture of what happens to groups of humans when their numbers drop below a certain threshold: we revert to more primitive means, losing the gains in culture and technology that we achieve when we have more of our fellow humans to exchange ideas (and genes) with. This, combined with our extended period of childhood (compared to other primates and, it is assumed, other early humans) may be what gave us the advantage over all of the other groups of our “cousins” that managed to hang on to their basic, set ways, for thousands of years but, in the end, could not adapt well (or rapidly) enough to avoid oblivion.
The nice (if we can call it that) thing about this conclusion is that it does make us feel a bit special for being, well, the ones that “won”. On the other hand, there rests beneath this understanding the uneasy realization that we were incredibly lucky. For the evidence also suggests that our lineage was down to just a few thousand individuals at times in our history (for more on this look up our “Mitochondrial Eve”). It also tells us that perhaps Homo Erectus or even the Neanderthal’s might have done equally well had they ever had the right “breaks” that allowed their numbers to expand.
The other stunning part of our story is how we went from being a fairly dispersed species of low population density for pretty much all of our history to numbering in the many billions in an astonishingly short time. That, somehow, once we got a foothold on our “modern” state of mind (and had developed the social structures and technology to support our increasing numbers) we went from one more smallish troop of naked apes to the dominant life form on the planet.
The “true” story of we modern humans is one of heartbreaking drama, and deeply humbling knowledge. Entire species of our fellow humans went extinct at different times (the Neanderthals as recently as 38,000 years ago, Homo Florensis — the “Hobbit” — perhaps only 8,000!). We lost our cousins (or drove them to the brink of extinction) the same as any other modern animal that stands as one of the survivors.
But we couldn’t even come to this picture of the many branches of our human family until we let go of the idea of a single-file, heroic march through time. Only then could we see the evidence for what it could actually tell us.
This capacity: the courage to see ourselves as we really are, is a huge achievement for us as a species, and perhaps we must give most of the credit to the objectivity of science, and the scientists themselves who have had to fight the same self-centered tendency that is shared by their entire species.
As time goes on, we will continue to discover more fossils. New technologies (and new knowledge) will wrest more information from those discoveries. It may well be (it must be, in fact, highly likely) that there will be even more dramatic twists and turns to our human story. But at least we are now, it seems, ready to hear the truth.
Dinosaurs look so strange. They look like something that lived in another world. It is a great part of our fascination with them: they are our familiar monsters. Monsters because of their size, for one, and their mysterious absence (but for fossil remains) for another. But they are also a bit familiar. They walk on two or four legs, after all, and have two eyes, a nose, two ears and a mouth (with plenty of teeth in the mouths of our favorites). So are they really so strange as we portray them to be?
I once attended a lecture by the director of the New Mexico Museum of Natural History about a huge herbivorous dinosaur whose bones were found in Northern New Mexico. At some point during the lecture, he mentioned that — like today — the Cretaceous prairies were populated by herds of herbivores that would have vastly outnumbered their carnivorous predators. Suddenly a light went off in my head, and the funny-looking duck-billed hadrosaurs went from being exotic dinosaurs to ancient wild cattle grazing like any buffalo or modern range cow: the “wild cows of the Cretaceous” (as I called them in my musical “EXTINCTION: A Love Story”).
This began a series of shifts in my thinking that steadily undermined my capacity to see ancient life forms as being any more odd in appearance than any animal living today. As if on cue, there then came the occasional chain e-mail or National Geographic article with a collection of photographs of the strangest-looking living things that have been found in our modern world. Turns out we don’t have to go back to the Cretaceous to find animals that look like they were built of spare parts late on a Friday afternoon at the biological assembly line. (See some in National Geographic HERE)
The situation is not much different from that of the foods that we eat. Each of us surely eats something (without a second thought) that would induce vomiting in another human from another spot on the earth.
The problem with seeing extinct species as completely un-related to us is that it can make it easier to dismiss the biological link that all life on earth shares. Now I’m not certain that it is really necessary that each living human feel a warm and fuzzy bond with the small 210 million-year old rodent that we appear to have descended from, but it couldn’t hurt.
Seeing myself as a part of not just the chain of current life, but of the history of life on the planet has given me a not insignificant comfort in the face of a universe that is seemingly incapable of regarding my existence. Whether the hungry tiger can appreciate it or not (as she decides how she’s going to snap my neck before eating me) we are brother and sister, in this parade of life together.
But that’s the rub: we humans are the animals who think about these things. Fortunately for us (and especially for certain cats and dogs), we have found other animals willing to abide our expressions of familial affection. And it is these animals that we consider the most familiar and pleasing to our eye and mind. Dolphins and whales appear very different from us, but perhaps it is their earlier life as four-footed, land-based ungulates (as well as their obvious intelligence) that makes it easier for us to consider them part of our family of “friendly” animals.
In contrast (Creationist exhibits of Velociraptors frolicking with children notwithstanding) we know full well that were we to come face to face with even the most intelligent raptor of the dino-age, the only meeting of minds would be that of our terrified brain and the raptor’s hungry one. To us, he would be a dinosaur: to the dinosaur, we would be just another animal. An exotic one, to be sure, but (as long as we weren’t armed with a man-made weapon) an ultimately easy one to catch, kill and eat.
But we are loathe to see ourselves as “just another animal”. This offends us in some way. We have a deep need to be special. So deep, in fact, that it’s not enough to be special on just on a local level: we must matter on a cosmic scale. We want to believe that a part of our selves lives on forever with our creator.
Honestly, I think this may be a fair trade-off for being saddled with a brain that can consider its own mortality. After all, what harm will it do in the long run? Yes, apocalyptic religious thought is currently gumming up the works like a giant wooden shoe in the gears of the sustainability problem solving machine, but in the end how much difference will that make on an earth scale measured in geologic time? Practically none.
(On that score, I think we humans are clever enough to stretch our time on earth by a considerable margin. After all, we have so far escaped the extinction that has been the inevitable norm for ninety-nine percent of every other animal that has ever lived on this small planet. And, barring another six-mile wide meteorite strike, we might just find a way to use our technological skill to survive the damage done by our technological skill. Seeing ourselves as the clever animals that we are would help enormously in that process, as it would strip away the false veil of differentness that we hang between us and every other thing in nature. After all, as you sit reading this, half of your body’s cellular weight is made up of bacteria (a fact that makes our current obsession with antibacterial gel seem a bit existentially absurd.))
We are as exotic as any species that ever walked the earth, with our odd bipedal, upright and naked bodies. With our flat faces, we may be the most unusual primate on the planet. And with our mutant brains, we have built our own un-natural world within a world in ways unmatched by any other creature. It’s no wonder we see ourselves as different. We are different! In tiny but significant ways. But whatever the differences between us and nature, they are minuscule when weighed against the most basic commonalities we share with every living thing.
Perhaps we are the strange creatures on this planet, and the other animals have just been too polite to tell us to our face.
REVIEWS FROM THE REV: “Why the Cheetah Cheats, And Other Mysteries of the Natural World” by Lewis Smith.Sunday, May 22nd, 2011
This 2009 book is a collection of one- and two-page stories from the natural world, both present and past. There is a little of everything in this book, from discoveries of new species to extinctions of existing ones (often from the introduction of non-native species by us world-traveling humans). There are tales of animal behavior, and examples of the power of evolution and natural selection to determine the characteristics of species.
The book is organized into general categories, but really it’s sort of a pleasant hodgepodge of interesting stuff that is easy to read through in bite-sized chunks.
I notice in this book (like others of late) a distinct lack of careful proofreading, which leads to more than one page turn that does not lead to the completion of the unfinished sentence from the previous page! I suspect this is an issue with books like this that are cranked out for the popular market.
I couldn’t find a website for the author, Lewis Smith, a journalist and author of a previous book: “Why the Lion Grew Its Mane, A Miscellany of Recent Scientific Discoveries from Astronomy to Zoology”.
The thing that stays with me about this book is the re-enforcement it gives to the raw reality of evolution, and just how specific adaptation to a particular environment can be, such that a change of just a few degrees in average temperature can doom a species, or the loss of one kind of bug can lead to the extinction of the tree species that has grown to depend on that particular bug (or bird, or animal) to carry its seeds about. Though parts of the book are clearly meant to alert us to the dangers of global climate change on susceptible species, it reminds me that all life has ever been susceptible to the slightest change in our environment, and that we alive today are the products of that blind process. Evolution continues.
Once upon a time there was a living organism that (after eons of evolution and natural selection) achieved a level of consciousness that brought with it the ability to both observe and contemplate her world. So this organism began to consider her environment: the mountains and valleys over which she traveled, the sky above, the air she breathed, the ground beneath her feet.
With others of her kind, she shared her observations and together they began to form an understanding of their own existence. Though based, at first, on speculation and imagination, over time their ideas came to be rooted more and more in evidence uncovered through scientific means.
They developed theories about the origins of life based upon the leftovers of evolution around them. They studied the organisms in their world that were similar (and different) from themselves for insights into their own behaviors, and from the evidence of their own past forms captured in their individual DNA they came to understand the ancestry that they shared with every other living thing.
They theorized, they experimented, they learned, and over time their knowledge began to increase at an ever accelerating pace, with each new discovery opening doors to more and more research. Through their knowledge and technology, their population began to explode: they lived longer, they lived healthier and they began to alter their environment to meet their needs.
Then one day the world they lived in seemed to change, as if there was a sickness upon the entire planet that they called home. The scientific evidence suggested that it was the very reproductive and technical success of these curious organisms that was causing the sickness. Others refused to believe it, and instead insisted it was part of a natural cycle that had happened before, and would happen again. In the end, the world that they lived in (and which they relied upon for their life) became so sick and weak that the organisms themselves began to die as their environment changed, forcing millions of them to uproot themselves and look for healthier environments to live.
The organism I’m imaging for this allegory this could be any one of the 90 trillion or so microbes with which we share our bodies, and their world (that they had struggled so diligently to comprehend) a single living human host who was made ill by a proliferation of deleterious microscopic flora.
The obvious analogy I draw is to us humans who have blossomed in such a short time into a global population of incredible technical and mental power but who, at the same time (hindered in no small part by the limitations of our evolved mammalian brain — see this week’s book review) have managed to put into motion two parallel runaway trains: one running toward an exciting future of scientific progress and the other toward a global climate (and resource) crisis that could easily make our pleasant lives here much less pleasant and even doubtful.
Where and when these “trains” are to intersect is up for debate. I’m afraid I tend toward a concern that such a collision is inevitable at some point. (After all, based on the evidence of history, even if we dodge this particular bullet there will inevitably be another).
The question that most immediately concerns me is of two parts: 1) are we racing toward a global event that will happen in my own lifetime and, 2) is there really anything that we humans can do about it — at this point?
Because, in a lot of ways, we are the microbes looking out at the world. Our planet is physically enormous compared to our own (relatively) tiny size, and beyond us is a vast universe that is barely comprehensible in scale. No less difficult to comprehend is the microbial ecosystem that we carry with us every day and night.
The crux of my worry is that our natural human tendency to see ourselves as the center of the universe is both blinding us to the fragility of the band of life we occupy on this planet and exaggerating our actual power to forestall the forces of climate change that we have managed to nudge into motion.
That is where the book I’ve reviewed this week (“Kluge: The Haphazard Construction of the Human Mind” by Gary Marcus) is both helpful and disturbing, as it reveals the many clunky ways in which the evolved human mind works. Though we humans are capable of reasonable and rational thought, we are still very much the primal animal that has to work at sorting the wheat from the chaff in terms of evidence and belief. And, frankly, I don’t think enough people are working hard enough at it!
To be clear, to me the question of whether or not I “believe” that this round of climate change has been caused by we humans (I tend to accept the science, of course) may be moot, as there seems to be a reality unfolding that should make even those who claim it’s a “perfectly natural” fluctuation in climate shit in their pants. (Species extinction is also perfectly natural, for that matter).
But I’m just one microbe tossing out his opinion about an ecosystem that is vast and complex, and hence my two-cents worth may be worth just about that much in the grand scheme of things. One thing, however, is for sure: we will soon enough find out how good modern scientists are at predicting global trends, and probably in the lifetime of many of us.
We live in interesting times, to be sure. And yet, no matter how hard I try, I can only see so much of it, and my glimpse is incredibly brief when measured against the march of time that we now know (through science) came before we humans were even here.
We are the clever, lucky microbes who get to be the ones to watch it all unfold. With a handful of other sentient creatures, we can think about our lives as they happen, and we can choose to live them in the best way we can.
Funny how no matter how vast life really is, the living of it will always be local, and personal. Whether we be microbe or human being.