Mystery of mysteries from the world of paleontology: Why do fossils of caimans in Panama indicate an animal migration from North to South America before there was a Panama Land Bridge and a Central America continental connection? The answer: The bridge was there earlier than previously thought. The animals walked, swam in fresh water rivers and lakes, or swam across very short saltwater bodies. Who cares?
Well, geologists, biologists, and paleontologists care. The story used to be that the Central American Land Bridge was a mere three million years old. If that were true, then a number of land and fresh water critters like caimans would have had a hard time getting from one continent to the other. But a recent geologic discovery by Camilo Montes and other scientists seems to push the formation of a land bridge back another ten million years or so. Northern Colombia has ancient sediments that rivers from Panama transported to South America (Science, 10 April 2015, Vol. 348 no. 6231, pp. 226-229). The Central American Seaway appears to have closed earlier than three million years ago. Migrating from north to south just meant walking.
Problem solved. Or, at least, problem redefined. The new evidence for an earlier land bridge seems pretty strong. But, if the conclusion is true, it presents another problem. How did the glacial epochs with their extreme cooling and warming episodes of the last 3 million years get their start? Previously, many scientists cited the closing of the connection between the Pacific and the Atlantic as a major contributor to the cooling. Such a closing of the seaway would have stopped the interchange of ocean currents between the two oceans and affected Northern Hemisphere climate. If the closing happened ten million years earlier, then a climate problem replaces the animal-exchange problem. If not a change in currents, then what caused temperatures to begin their erratic teeter-tottering between high and low extremes at least ten times during the last two to three million years?
Isn’t that the way of the world? You solve one problem, but your solution creates another problem—or at least an unintended effect. Won’t there ever be equilibrium? Won’t the seesaw balance?
Disequilibrium is the way of the world. Balance something, and watch something else become imbalanced. Please someone, and watch displeasure grow in someone else. Make peace with one country at the expense of becoming an enemy of another one. The horizontal seesaw of knowledge and belief is temporary at best. The seesaw of human connections is usually tilted.
Well, geologists, biologists, and paleontologists care. The story used to be that the Central American Land Bridge was a mere three million years old. If that were true, then a number of land and fresh water critters like caimans would have had a hard time getting from one continent to the other. But a recent geologic discovery by Camilo Montes and other scientists seems to push the formation of a land bridge back another ten million years or so. Northern Colombia has ancient sediments that rivers from Panama transported to South America (Science, 10 April 2015, Vol. 348 no. 6231, pp. 226-229). The Central American Seaway appears to have closed earlier than three million years ago. Migrating from north to south just meant walking.
Problem solved. Or, at least, problem redefined. The new evidence for an earlier land bridge seems pretty strong. But, if the conclusion is true, it presents another problem. How did the glacial epochs with their extreme cooling and warming episodes of the last 3 million years get their start? Previously, many scientists cited the closing of the connection between the Pacific and the Atlantic as a major contributor to the cooling. Such a closing of the seaway would have stopped the interchange of ocean currents between the two oceans and affected Northern Hemisphere climate. If the closing happened ten million years earlier, then a climate problem replaces the animal-exchange problem. If not a change in currents, then what caused temperatures to begin their erratic teeter-tottering between high and low extremes at least ten times during the last two to three million years?
Isn’t that the way of the world? You solve one problem, but your solution creates another problem—or at least an unintended effect. Won’t there ever be equilibrium? Won’t the seesaw balance?
Disequilibrium is the way of the world. Balance something, and watch something else become imbalanced. Please someone, and watch displeasure grow in someone else. Make peace with one country at the expense of becoming an enemy of another one. The horizontal seesaw of knowledge and belief is temporary at best. The seesaw of human connections is usually tilted.
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