The environment is an example that's been of concern for a long time. Yet nature has an amazing ability to heal itself and adapt to situations we would think are unbearable as the following examples show.
Evolution is usually thought of as occurring over long time periods, but it can also happen quickly. Consider a tiny fish whose transformation after the 1964 Alaskan earthquake was uncovered by University of Oregon scientists and their University of Alaska collaborators. The earthquake made some parts of the Pacific into ponds on a few islands,. Fifty years later and the fish in those ponds are now freshwater fish. Apparently the genes for dealing with that sort of wild extreme change are held by some of the fish in the crowd and natural selection can work its wonders in a decade. (1)
As Joanne Nova notes,”In terms of ocean acidification, this is as catastrophic as it gets, not only did the ocean become 'more acidic' but it stopped being an ocean. It can't get much worse than this for a fish, and yet somehow life on Earth had the answer. What's the pH of those ponds? The ocean pH is 8.1, rain is 5.5. Those ponds will be somewhere in between.” (2)
“We've moved the timescale of the evolution of stickleback fish to decades, and it may even be sooner than that,” said UO biologist William Cresko, whose lab led the National Science Foundation funded research. “In some of the populations that we studied we found evidence of changes in fewer than even 10 years. This indicates that evolutionary change can happen quickly, and this likely has been happening with other organisms as well.” (3)
Worms in Foundry Cove on the Hudson River are one of those other examples. Between 1953 and 1970 industry in the area dumped more than 100 tons of nickel-cadmium waste into the cove and nearby river. Arsenic, lead and other toxins were also dumped into the river.
Jeffrey Levinton found that as much as 25% of the cove's bottom sediment dwelling consisted of cadmium, which is highly toxic. Yet, many bottom dwelling invertebrates were present in numbers no fewer than in unpolluted ares at other sites. In an effort to learn why, Levinton investigated the cadmium tolerance of other earthworms. Whereas local cove worms thrived and reproduced, worms from a nearly cove showed clear signs of distress or died when placed in Foundry Cove. Yet, offspring of Foundry cove worms raised in clean muds were tolerant of cadmium, leading to the conclusion that genes were largely responsible for the tolerance. This degree of metal tolerance could have evolved in just 2 to 4 generations, or a couple of years. (4)
Levinton states that this capacity for rapid adaptation in the face of novel environmental challenge was startling, since no population of worms in nature has ever faced conditions like this one humankind created in Foundry Cove.
Furthermore, although some species inhabiting nearby waterways are missing from Foundry Cove, most adapted to the unusual conditions. Just 100 yards downstream is an Audubon Society sanctuary for migrating birds which has prospered.
Another report shows that worms can encapsulate heavy metals before excreting them, which leaves the metals isolated in a hard shell. This is what happened after the Chernobyl nuclear accident, and why the local environment looks so good now. (5)
In addition, worms from Chernobyl may have changed their sexual behavior to increase their chances of survival. This is one of the first pieces of direct evidence on how wildlife is affected by radioactive pollution. Research suggest that the worms switched from asexual to sexual reproduction as they are capable of doing, and this was an attempt to protect themselves from radiation. (6)
Nature has also demonstrated the capacity for natural recovery from an atomic holocaust. T. D. Luckey reports the remarkable survival of a rat colony on Enjebi Island in the Eniwetok atoll. Enjebi is part of the Marshall Islands and site of the “X-ray Nuclear Test” in 1948 during Operation Sandstone. Within one year following four nuclear explosions, healthy rats emerged from the protection of cable tunnels. Pregnancy rates, sex ratios, and average number of embryos per litter were comparable with those found before the four nuclear devastations. The colony rapidly expanded to fill the 250 acre island. No mutations were observed. (7)
Dixy Lee Ray discusses a colony of rats that occupy a mound in the Brazilian area of Morr do Ferro. This is a weathered mound, 250 meters tall that contains an estimated 30,000 metric tons of thorium and 100,000 tons of rare metals. The radiation level is so high tht autoradiographs (photographs produced by radiation) show plants on the mound actually glowing in the dark. The overall radiation dose they receive is roughly three times the concentration that should produce tumors or other radiation effects. Yet, no abnormalities were found in the rats that were trapped and autopsied. (8)
Summary
These examples open a new window on how climate change could affect all kinds of species. It shows that organisms—even vertebrates with long generation times—can respond very fast to environmental change.
Jack Dini
Livermore, CA
References
1. Emily A. Lescak et al., “Evolution of stickleback in 50 years on earthquake-uplifted islands,”
PNAS, December 14, 2015
2. Joanne Nova, “Life adapts—fish evolved from salt to fresh water in just fifty years,” joannenova.com, December 17, 2015
3.”Small fish species evolved rapidly following 1964 Alaska earthquake,” sciencedaily.com, December 14, 2015
4. Jeffrey S. Levinton, “The big bang of animal evolutions,” Scientific American, 267, 84, November 1982
5. Ivo Vegter,
Extreme Environment, (Cape Town, South Africa, Zebra Press, 2012), 128
6. “Only in Ukraine,” onlyukraine.blogspot.com, September 4, 2006
7. T. D. Luckey,
Radiation Hormesis, (Boca Raton, CRC Press, 1991), 65
8. Dixy Lee Ray, “Radiation around us,” in
Rational Readings on Environmental Concerns, Jay H. Lehr, Editor, (New York, Van Nostrand Reinhold, 2000), 594
