Rolling the dice with evolution
by mwmwm, Daily Kos, September 3, 2010
A new study by J. Alroy, just published in Science (subscription required for full text), has been getting some reporting by other sources. It's mildly entitled "The Shifting Balance of Diversity Among Major Marine Animal Groups."
It prods me to my keyboard.
Evolution, and biodiversity, and the interrelationships of biosystems, are to me the imprint of the universe's organizing principles. It's what I grew up with instead of religion.
My father was an evolutionary biologist and animal behaviorist, and so I grew up with dinnertime discussions about evolutionary pressures on butterfly wing designs, or the evolutionary explanations for beehive altruism, or why mating behavior affected peacock feather development.
Elroy's analysis -- while not a surprise -- hit me surprisingly hard, because it drove home the full impact of the "sixth extinction."
It prods me to my keyboard.
Evolution, and biodiversity, and the interrelationships of biosystems, are to me the imprint of the universe's organizing principles. It's what I grew up with instead of religion.
My father was an evolutionary biologist and animal behaviorist, and so I grew up with dinnertime discussions about evolutionary pressures on butterfly wing designs, or the evolutionary explanations for beehive altruism, or why mating behavior affected peacock feather development.
Elroy's analysis -- while not a surprise -- hit me surprisingly hard, because it drove home the full impact of the "sixth extinction."
I've long known about what's become called the "sixth extinction" -- a.k.a. the "Holocene extinction" -- the one humans are currently creating. (Heck, it's a specific tag that we've had on the ApocaDocs site since we began it.)
Over the past 540 million years or so on Earth, there have been five previous massive extinction events. The most recent was the one that wiped out the dinosaurs, 65 million years ago, which allowed the first tiny mammals to thrive, and set the stage for the ecosystem we live in today.
Apart from cataclysmic catastrophes of one sort or another, evolution slowly allows the development of generation after generation of slightly different, slightly more specialized (or generalized), slightly more advantageous changes in populations of species. Occasionally there are blips of diversity, or localized pressures that create unusual oddities, but for the most part it's the way life, in all its forms, adapts to threats and opportunities in the ecosystem. In general, it produces a relative equilibrium of biodiverse life.
What this new study explores is how different each extinction event has been, how unpredictable the outcomes are, and acknowledges how dramatically (and thoughtlessly) humans are now changing the rules of evolution for the future, in the world we inhabit today.
From Wired, "Mass Extinctions Change the Rules of Evolution":
Or it may seem obvious that evolution can only move forward with what DNA it has in its bank, and so a radical reboot to a new biospheric operating system will obviously result from this Holocene extinction -- the one we're in, and that we're creating.
As the Wired article continues,
Randomly. Unpredictably. As if we randomly cut off most of our fingers.
We've all been watching this, of course, but not thinking much about it. We think in timescales of a generation or two. We don't remember the incredible bounty of the land and the sea in the late 1800s. We don't recall what's been lost, nor do we understand what we're creating.
We are creating a new baseline for the next several million years, by our actions and inactions. Whether through massive production of CO2, plastic, or chemical disruptors; through overfishing, overfertilizing, or overextracting; or through deforestation, trawling, or mountaintop mining, we are taking a radical stance.
We're saying to the previous 65 million years of evolutionary development -- the years that evolved meadowlarks, marmosets, marlins, and millipedes, hawks, hammerheads, honeybees, and humans... we're saying to those 65 million years of evolution, fuck you.
"We're remaking the rules. We'll cut off whatever fingers you have, as we will. Fuck you and whatever you consider important."
It's what Mao did when he implemented China's "Cultural Revolution": destroy the past, so we can start fresh. Burn pianos, books, urns, antiques, paintings, scrolls, philosophy, poetry, art, burn it all, so we can start fresh. What was lost in that great burning is incalculable.
And we aren't even burning down the world intentionally. We are clueless, blinkered, and rushing headlong toward systematically extinguishing the wild, diverse life around us. We are burning up all that came before, just because it's convenient.
The next million years of evolution will bear the unmistakable stain of the mindlessness of humans, during our brief ascendancy. Soon, it will (in a few hundred thousand years or so) become the new normal.
Will we have oceans full of competing jellyfish, rather than vertebrates? Will insects explode in size and diversity, or just in numbers? Will we catalyze plagues of predator-prey imbalances, wiping out dependencies we didn't know existed? Will smart, omnivorous crows become the starting point for all birds after that, as the specialized ones die off?
We, of course, won't know. But we will have functionally erased the ecosystem that bred us, and created a new ecosystem foundation, whose implications we cannot understand.
It is conceivable that humans can pull ourselves back from the worst of this. We can live more lightly, and more thoughtfully and slowly. But it will take all of us reshaping our approach to the world consciously, with more respect for our elders -- our elders going back 65 million years.
Would we ever say "fuck you" to our great-grandparents?
Never, unless we're sociopaths.
Link: http://www.dailykos.com/story/2010/9/3/898742/-Rolling-the-dice-with-evolution
Over the past 540 million years or so on Earth, there have been five previous massive extinction events. The most recent was the one that wiped out the dinosaurs, 65 million years ago, which allowed the first tiny mammals to thrive, and set the stage for the ecosystem we live in today.
Apart from cataclysmic catastrophes of one sort or another, evolution slowly allows the development of generation after generation of slightly different, slightly more specialized (or generalized), slightly more advantageous changes in populations of species. Occasionally there are blips of diversity, or localized pressures that create unusual oddities, but for the most part it's the way life, in all its forms, adapts to threats and opportunities in the ecosystem. In general, it produces a relative equilibrium of biodiverse life.
What this new study explores is how different each extinction event has been, how unpredictable the outcomes are, and acknowledges how dramatically (and thoughtlessly) humans are now changing the rules of evolution for the future, in the world we inhabit today.
From Wired, "Mass Extinctions Change the Rules of Evolution":
A reinterpretation of the fossil record suggests a new answer to one of evolution’s existential questions: whether global mass extinctions are just short-term diversions in life’s preordained course, or send life careening down wholly new paths.
Some scientists have suggested the former. Rates of species diversification — the speed at which groups adapt and fill open ecological niches — seemed to predict what’s flourished in the aftermath of past planetary cataclysms. But according to the calculations of Macquarie University paleobiologist John Alroy, that’s just not the case.
"Mass extinction fundamentally changes the dynamics. It changes the composition of the biosphere forever. You can’t simply predict the winners and losers from what groups have done before," he said.This may seem obvious: well, duh, randomly chop off five to eight of your ten fingers, and you may end up with no thumbs -- which kinda limits the type of work you can do.
Or it may seem obvious that evolution can only move forward with what DNA it has in its bank, and so a radical reboot to a new biospheric operating system will obviously result from this Holocene extinction -- the one we're in, and that we're creating.
As the Wired article continues,
And while his data supported the notion that each group’s diversity eventually hits a limit, he didn’t find Sepkoski’s correlation between pre-mass-extinction diversity rates and post-extinction success. Each mass extinction event seemed to change the rules. Past didn’t indicate future.
...
Starting with extinctions of large land animals more than 50,000 years ago that continued as modern humans proliferated around the globe, and picking up pace in the Agricultural and Industrial ages, current extinction rates are far beyond levels capable of unraveling entire food webs in coming centuries. Ecologists estimate that between 50 and 90 percent of all species are doomed without profound changes in human resource use.
In the past, many evolutionary biologists thought life would eventually recover its present composition, said Alroy. In 100 million years or so, the same general creatures would again roam the Earth. "But that isn’t in the data," he said.So the rather minuscule 50,000 years that we humans have been on the earth can be seen as a cataclysmic event, across the entire ecosystem, that will fundamentally rewire the starting points of evolution from here on out.
Randomly. Unpredictably. As if we randomly cut off most of our fingers.
We've all been watching this, of course, but not thinking much about it. We think in timescales of a generation or two. We don't remember the incredible bounty of the land and the sea in the late 1800s. We don't recall what's been lost, nor do we understand what we're creating.
We are creating a new baseline for the next several million years, by our actions and inactions. Whether through massive production of CO2, plastic, or chemical disruptors; through overfishing, overfertilizing, or overextracting; or through deforestation, trawling, or mountaintop mining, we are taking a radical stance.
We're saying to the previous 65 million years of evolutionary development -- the years that evolved meadowlarks, marmosets, marlins, and millipedes, hawks, hammerheads, honeybees, and humans... we're saying to those 65 million years of evolution, fuck you.
"We're remaking the rules. We'll cut off whatever fingers you have, as we will. Fuck you and whatever you consider important."
It's what Mao did when he implemented China's "Cultural Revolution": destroy the past, so we can start fresh. Burn pianos, books, urns, antiques, paintings, scrolls, philosophy, poetry, art, burn it all, so we can start fresh. What was lost in that great burning is incalculable.
And we aren't even burning down the world intentionally. We are clueless, blinkered, and rushing headlong toward systematically extinguishing the wild, diverse life around us. We are burning up all that came before, just because it's convenient.
The next million years of evolution will bear the unmistakable stain of the mindlessness of humans, during our brief ascendancy. Soon, it will (in a few hundred thousand years or so) become the new normal.
Will we have oceans full of competing jellyfish, rather than vertebrates? Will insects explode in size and diversity, or just in numbers? Will we catalyze plagues of predator-prey imbalances, wiping out dependencies we didn't know existed? Will smart, omnivorous crows become the starting point for all birds after that, as the specialized ones die off?
We, of course, won't know. But we will have functionally erased the ecosystem that bred us, and created a new ecosystem foundation, whose implications we cannot understand.
It is conceivable that humans can pull ourselves back from the worst of this. We can live more lightly, and more thoughtfully and slowly. But it will take all of us reshaping our approach to the world consciously, with more respect for our elders -- our elders going back 65 million years.
Would we ever say "fuck you" to our great-grandparents?
Never, unless we're sociopaths.
Link: http://www.dailykos.com/story/2010/9/3/898742/-Rolling-the-dice-with-evolution
No comments:
Post a Comment