The Next Species: The Future of Evolution in the Aftermath of Man Read Online Free Page A
Author: Michael Tennesen
smooth bodies spread over much of the land with giant swordfish-like fins on their back for capturing the sun.
The Permian world was a lively one, as proven by the numerous fossils that adorn the earthen walls of McKittrick Canyon. But something caused the annihilation of most of these animals.
THE SECOND CREATION OF LIFE
The Capitan Reef that decorates the top of the Guadalupe Mountains above McKittrick Canyon is similar to the structure of Mount Rushmore, only carved not with US presidents but with the force of life that thrived before the mass extinction. Yet the rocks in McKittrick Canyon do not display evidence of the end of the Permian.
To see that, Sam Bowring, a bearded and amiable professor of geology whom I visited earlier at MIT, had to travel to China. Bowring showed me a photo of himself and Zhu Zhuli, a Chinese researcher, in Meishan, standing on the face of a rock quarry. Zhuli had his feet on a dark line in the rock that represented the end of the Permian. The change in color was caused by a dramatic change in the geology and chemistry of the rock. It was the geological boundary line between the Permian and the Triassic periods, the point where one era of life encased in sediments of earth ceased to exist and another was laid down on top of it. In the photo, Bowring stood above the line in early Triassic ash beds. It is one of thebest-studied Permian-Triassic boundary sequences in the world. Fully 333 species have been identified in the fossils below where these two scientists were perched. But above that line almost all of them disappear, an extinction rate of 94 percent.
John Phillips, a mid-nineteenth-century English geologist whopublished the first global geological time scale, found that the fossils were so different on either side of the Permian-Triassic boundary that he referred to the line in the stratigraphic layers that Bowring stood above and the difference in fossils on either side as the Second Creation of Life. He never saw the line in Meishan, China, but had studied this event at similar stratigraphic sites elsewhere in the world.
The catastrophe that created this boundary has similarities to the destruction humans are inflicting through greenhouse gas buildup, ocean acidification, and global warming. No, it wasn’t a giant spectacular meteor falling out of the sky. The primary villain of the Permian extinction was the Siberian Traps.This eruption occurred about 252 million years ago, according to new findings from Bowring. At that time a viscous magma flowed out of the ground and spread over the land, filling in the valleys and basins around it like honey finds the crevices on a piece of toast. The total amount of lava flow was mind-boggling. In one area it grew 6,500 meters thick, almost four miles. “In the end it covered much of Siberia, an area close to the size of the continental United States,” Bowring told me.
Still, there was not just a single cause to this extinction. It was more the perfect storm, the coming together of multiple perpetrators, as it has been with other extinction events. The lava that created the traps burned up through an enormous coal reserve at its center, and the heat of the molten lava converted much of the black rock to CO 2 . But as temperatures rose, some of that coal would have converted to methane, which is twenty times more potent a greenhouse gas than CO 2 , and this would have accelerated warming.
The end result of the buildup of CO 2 and methane, among other causes, was one of the few mass extinctions of insects in earth’s history. Their numbers descended from sixty families during the height of the Permian period to almost zero at the end of it. The air was silent, since birds had yet to evolve. The coal that had thrived in the marshy environments and plentiful vegetation disappeared as the earth grew drier. Whole forests and entire ecosystems of plants died but fungi flourished, since they fed off the dead plant and animal matter.
Though
The Permian world was a lively one, as proven by the numerous fossils that adorn the earthen walls of McKittrick Canyon. But something caused the annihilation of most of these animals.
THE SECOND CREATION OF LIFE
The Capitan Reef that decorates the top of the Guadalupe Mountains above McKittrick Canyon is similar to the structure of Mount Rushmore, only carved not with US presidents but with the force of life that thrived before the mass extinction. Yet the rocks in McKittrick Canyon do not display evidence of the end of the Permian.
To see that, Sam Bowring, a bearded and amiable professor of geology whom I visited earlier at MIT, had to travel to China. Bowring showed me a photo of himself and Zhu Zhuli, a Chinese researcher, in Meishan, standing on the face of a rock quarry. Zhuli had his feet on a dark line in the rock that represented the end of the Permian. The change in color was caused by a dramatic change in the geology and chemistry of the rock. It was the geological boundary line between the Permian and the Triassic periods, the point where one era of life encased in sediments of earth ceased to exist and another was laid down on top of it. In the photo, Bowring stood above the line in early Triassic ash beds. It is one of thebest-studied Permian-Triassic boundary sequences in the world. Fully 333 species have been identified in the fossils below where these two scientists were perched. But above that line almost all of them disappear, an extinction rate of 94 percent.
John Phillips, a mid-nineteenth-century English geologist whopublished the first global geological time scale, found that the fossils were so different on either side of the Permian-Triassic boundary that he referred to the line in the stratigraphic layers that Bowring stood above and the difference in fossils on either side as the Second Creation of Life. He never saw the line in Meishan, China, but had studied this event at similar stratigraphic sites elsewhere in the world.
The catastrophe that created this boundary has similarities to the destruction humans are inflicting through greenhouse gas buildup, ocean acidification, and global warming. No, it wasn’t a giant spectacular meteor falling out of the sky. The primary villain of the Permian extinction was the Siberian Traps.This eruption occurred about 252 million years ago, according to new findings from Bowring. At that time a viscous magma flowed out of the ground and spread over the land, filling in the valleys and basins around it like honey finds the crevices on a piece of toast. The total amount of lava flow was mind-boggling. In one area it grew 6,500 meters thick, almost four miles. “In the end it covered much of Siberia, an area close to the size of the continental United States,” Bowring told me.
Still, there was not just a single cause to this extinction. It was more the perfect storm, the coming together of multiple perpetrators, as it has been with other extinction events. The lava that created the traps burned up through an enormous coal reserve at its center, and the heat of the molten lava converted much of the black rock to CO 2 . But as temperatures rose, some of that coal would have converted to methane, which is twenty times more potent a greenhouse gas than CO 2 , and this would have accelerated warming.
The end result of the buildup of CO 2 and methane, among other causes, was one of the few mass extinctions of insects in earth’s history. Their numbers descended from sixty families during the height of the Permian period to almost zero at the end of it. The air was silent, since birds had yet to evolve. The coal that had thrived in the marshy environments and plentiful vegetation disappeared as the earth grew drier. Whole forests and entire ecosystems of plants died but fungi flourished, since they fed off the dead plant and animal matter.
Though
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