Readers Respond to "When the Sea Saved Humanity" and Other Articles

Letters to the editor from the August 2010 issue of Scientific American

Blowing the Whistle
In “Danger in School Labs” [News Scan], Beryl Lieff Benderly lists four fatalities from lab accidents. She notes that the Protecting America’s Workers Act would expand the jurisdiction of the Occupational Safety and Health Act of 1970 to include state employees, in particular those of state colleges and universities. Whistleblower protections would also improve. Sadly, 5,000 Americans die every year from workplace hazards. Sadder still, although dead bodies usually get Congress to pass better protections, opposition from the U.S. Chamber of Commerce has mired the bill in committees.

Under the 1970 act, whistleblowers can file a complaint with the Occupational Safety and Health Administration, but if OSHA decides not to take any further action in the case, the whistleblower has no further rights to any hearing or appeal. This dependence on OSHA has been devastating for the vast majority of workers who face retaliation after raising safety concerns.

In certain facilities, such as nuclear power plants, strong whistleblower protections already give workers in environmentally sensitive jobs meaningful legal remedies when they face retaliation for raising safety and compliance concerns. The new act would establish similar protections for all the employees OSHA covers in both the public and private sectors. When whistleblowers speak truth to power, they could finally hold employers accountable when they choose to retaliate. Our legislators need to know that lives are more important than Chamber of Commerce opposition.
Richard R. Renner
Legal director
National Whistleblowers Center
Washington, D.C.

Human Bottleneck
In “When the Sea Saved Humanity,” Curtis W. Marean mentions that everyone alive today descended from a group of people from a single region who survived a cold, dry spell that went on between 195,000 and 123,000 years ago. But in the same issue, in Michael Shermer’s Skeptic column “Our Neandertal Brethren,” we learn that we are the descendants of a population of hominids that migrated into Europe some 400,000 years ago and another population from Africa that migrated between 80,000 and 50,000 years ago. How can one reconcile both theories?
Lionel Lecoq
Basel, Switzerland

MAREAN REPLIES: In my article I described how, between roughly 190,000 and 130,000 years ago, the modern human lineage (at that time restricted to Africa) was bottlenecked to a small breeding population, apparently during a strong glacial phase. When that glacial phase ameliorated at about 125,000 years ago, this small population expanded and spread throughout Africa. A subgroup of this expanding population eventually squeezed its way out of Africa into the Middle East, and from there those immigrants went on to Europe and East Asia.

As Shermer describes, Neandertal genome studies suggest that when this intrepid group of modern humans dispersed from Africa they encountered Neandertals in an intimate manner. The result was genetic leakage from the Neandertal line into the modern human genome, and this was carried throughout the non-African lineages and maintained, perhaps because it carried with it adaptive advantages. All modern humans descend from the small group that survived the bottleneck; however, in the case of people of European and Asian background, that lineage is not “pure,” because our ancestors interbred with Neandertals. The Nean­der­tal results highlight how scientists’ strict definitions of fossil and living species do not always fit together well.

Marean describes his and his colleagues’ investigation at Pinnacle Point, South Africa, and notes that the current vegetation of the region is highly diverse and includes a large number of species that are characterized by edible root tubers and bulbs, that is, geophytes.

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