McNeil states that we may be in the early stage of the Sixth Mass Extinction Event on Earth, but the bright side is that there are always some survivors of mass extinctions. McNeil tells us of the 1/10 of marine life which survived the Greatest Extinction Event on the planet; reminding us that all life which is supported by oxygen owes its existence to the cyanobacteria that increased oxygen concentration in the air from 1 part per trillion to the 1 in 5 we currently enjoy. Humans may have improved life for 40 animals and 100 plant species, but we’ve instigated the most substantial Extinction Event to date, probably. The experts are laying their bets on viruses and bacteria, and maybe some cockroaches as the future inhabitants of Earth.
As chapter 7 and 8 takes us on a tour of the known causes of the destruction of the Biosphere, we learn that one of humanities major challenges has been disease and developing immunities. One of the reasons that viruses may succeed us as the dominant species on the planet is the ability to make rapid evolutionary changes to survive.
“It is possible that the prevalence of influenza in recent centuries derives from the close quarters kept by ever more ducks, pigs, and people, mainly in China.” (McNeil 210)
Before the recent outbreak and health concern over the H1N1 virus was dominating the headlines, the H5N1 avian flu virus stopped traffic into and out of China. Influenza viruses effected the duck population across Asia. Viruses seen in the avian population have crossed over to swine, in the past, (1979, 1998), and then crossed the species barrier once again to humans.
“From late 2003 through January 2004, H5N1 influenza viruses spread in an unprecedented manner across Asia, affecting poultry in Vietnam, Thailand, Indonesia, China, Japan, South Korea, Cambodia, and Laos. Hundreds of millions of chickens and ducks were culled in an effort to stop the spread. The outbreak appeared largely under control in March 2004. The available evidence shows that H5N1 infection is widespread among domestic ducks in southern China and may therefore be endemic in domestic ducks throughout Southeast Asia.” (Huise-Post 1)
Researchers believe that it is the virus’ ability to evolve and change mode of transmission as well as changing infection cycles that have contributed to the widespread problem.
“Wild waterfowl are generally thought to transmit influenza viruses primarily through fecal contamination of water. However, ducks inoculated with the 2002 H5N1 influenza viruses shed more virus from the trachea than from the cloaca. This property was retained in all of the viruses we tested.” (Huise-Post 3)
McNeil points out that “by 1990 some 25,000 antibiotics existed, curtailing microbial careers and improving human and animal health.” (McNeil 199) Without public health measures, many more masses of people could have perished in the modern era, as we have seen in the past when native populations have encountered colonialists and foreign germs. Public health measures may not be enough to stop MDR viruses and other strains that evolve in one transmission cycle.
“Highly pathogenic H5N1 viruses in our study became nonpathogenic to ducks after extended shedding shows that these viruses are moving toward stability in this host. Because this mechanism increases the potential for spread of these viruses, it is biologically significant, helping to explain the origin of new H5N1 viruses and the manner in which they become the dominant viruses in a quasi-species population.” (Huise-Post 4)
As each day passes we become more and more interconnected due to the decrease in available resources and necessities of life, McNeil asserts that if we don’t make major changes in our aggregate behavior, (on the scale of billions of people), “30-50 percent of terrestrial species may disappear in the next century or two.” (McNeil 263) Wade explained to us that rapid evolutionary change has never been adaptive for humans because our environments, (umbworlds), do not change rapidly, usually. With something new under the sun, it maybe that the organism, (virus), best equipped to change with a rapidly changing environment will be the most fit of them all.
Works Cited:
Huise-Post, D., Sturm-Ramirez, K., Humberd, J., Seiler, P., Govorkova, E., Krauss, S., et al. (2005). Role of domestic ducks in the propagation and biological evolution of highly pathogenic H5NI influenza viruses in Asia. Proceedings of the National Academy of Sciences of the United States of America, 102(30), 10682-10687. doi:10.1073/pnas.0504662102.
McNeil, J.R. Something New Under The Sun. New York: W.W. Norton & Company, Inc., 2000. Print.
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