The rapid evolution of technology has dramatically outpaced the biological evolution of most species, including humans. The sudden rise of new toxins into the environment has created an evolutionary hangover of unknown proportions.
The term evolutionary hangover has stemmed from the thought that evolution does not possess foresight, it instead is adaptive to the environment, which is not always done in a timely manner. According to Paul R. Ehrlich, “We have evolutionary hangovers when cultural evolution makes deleterious changes in our environment more rapidly than genetic evolution can respond to them. Some of the rapid environmental changes brought about by industrialization seem to have caused an increased incidence of cancer in human populations” (Ehrlich 2000, 35). He continues, “…selection could not preadapt our species to withstand much of the chemical assault to which it is now subjected because that assault is totally unprecedented. Earth is now awash in millions of tons of novel synthetic chemicals…Many of them are toxic, carcinogenic, or mutagenic (damaging to genetic material) or cause developmental problems...” (Ehrlich 2000, 36).
An example of one type chemical that has been created and released into the environment are Polybrominated diphenyl ethers (PBDEs) which are used as flame retardants in many everyday products. PBDEs have been found globally in human samples, mostly in breast milk, and are known endocrine disruptors (Darnerud 2008). An evolutionary hangover is present when a chemical is released and is harming a species, in this case humans, because they have not yet evolved a resistance or immunity to its affects. Slow evolution rates in humans keep them from having the ability to evolve as quickly as these chemicals are being created. New toxins are produced constantly, presenting an unknown future for humans.
Darnerud, P. O. 2008. Brominated flame retardants as possible endocrine disruptors. International Journal of Andrology 31, no. 2 (April). http://web.ebscohost.com.libaccess.sjlibrary.org/ehost/pdf?vid=28&hid=9&sid=2906b662-46ca-40e9-acf0-c4524f94ccdd%40sessionmgr110 (accessed August 29, 2009).
Ehrlich, Paul R. 2000. Human Natures: Genes, Cultures, and the Human Prospect. New York: Penguin. http://f1.grp.yahoofs.com/v1/oC6bSjFXie0Oaj6A3Py1Lo46GbwOBeBHqynKRaRPIPrCIKlPiUkZIBURzLKQUESF53N6SkJmxVkzagSAVYGHyropKqm_QpvD1lueQA/Readings/PDF2%3FEhrlich%20Ch2.pdf (accessed August 29, 2009).
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I find the article very interesting knowing that there are more chemicals and toxins in the environment and that they do effect health, but looking at it from evolutionary standpoint it is not severely as bad as it seems. Ehrlich uses the example of fruit flies and DDT, to show how species can adapt to survive. Colonies of fruit flies were treated with DDT with only a few survivors. Those survivors have genetic immunity from DDT which is then passed on to offspring. The same may be true for humans. Genetic drift and variation will allow future generations to become "toxic tolerant".
ReplyDeleteThis post is excellent. I firmly believe that globalization is a big contributor to this issue because not only is technology taking over certain human labor; it is taking over our environment as well. The "good enough" ideology that we are wired to perform is starting to hurt us by effecting our umworld that we live in.
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