CSB#2: When the Sea Saved Humanity - Madhu Nori

Definitions:

• MIS6: Marine Isotope Stage 6 - A period 195,000 years ago when the earth's conditions began to deteriorate and the planet went into a glacial stage. This period lasted until about 123,000 years ago.
• Paleoanthropologist: Someone who studies a branch of anthropology, or human kind and their evolution, concerned with fossil hominids.
• Homo Sapiens: The primate species to which modern humans belong.

Summary:

• At some point between 195,000 and 123,000 years ago, the population size of Homo sapiens plummeted perilously-from more than 10,000 breeding individuals to just hundreds, thanks to cold, dry climate conditions that left much of our ancestors' African homeland uninhabitable. The harsh climate conditions nearly extinguished our species.
• Everyone alive today is descended from a group of people from a single region who survived this catastrophe.
• The southern coast of Africa would have been one of the few spots where humans could survive during this climate crisis, because it harbors an abundance of shellfish and edible plants.
• This region is called Pinnacle Point, a promontory near the town of Mossel Bay that juts into the Indian Ocean
• Shellfish, which are rich in protein, are thought to have aided survival of the Pinnacle Point population because they abound year-round in the rocky intertidal zone along the southern coast of Africa. Brown mussels have turned up in even the earliest levels of PP13B, dating to 164,000 years ago, revealing that humans began exploiting marine resources earlier than previously thought.
• Excavations of a series of sites in Pinnacle Point, Africa, such as PP13B and caves 5-6, have recovered items left behind by what may have been that progenitor population.
• Finding archaeological sites dating to glacial stage 6 required searching for shelters that were close enough to the sea to allow relatively easy access to shellfish yet elevated enough that their ancient remains would not have washed away when the sea level rose 123,000 years ago.
• The results from these excavations highly prove that the human population did, in fact have a major drop about 195,000 years ago.
• The discoveries confirm the idea that advanced cognitive thinking evolved earlier than previously thought, and may have played a key role in the survival of homo sapiens during tough times.

Discussion:

• I think that it's really cool how we are all descended from that tiny group of homo sapiens that survived the MIS6.
• Basically, this article is telling us that we all originated in Africa. This intrigues me as Africans have very different facial features compared to Europeans or Asians, for example.
• It's interesting that, even 195,000 years ago, our ancestors were actually smart enough to find new habitats in which they could survive. They also made stone tools and lived in caves.
• It's scary that the homo sapiens species almost completely died off because of the MIS6. if they had actually died off, then we wouldn't be here, dominating the earth. This just shows how bad the consequences of global warming could be for us humans.

Questions:

• How were they able to migrate and successfully find new habitable land in time before they died out?
• How is it possible that a global population approaching 7 billion is all descended from a group of only a few hundred people?

Sources:

• Marean, Curtis W. "When the Sea Saved Humanity." EBSCO Host. Scientific
  American, Aug. 2010. Web. 14 Oct. 2010. .