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target="_blank" rel="nofollow" href="#ulink_d73ac442-f40c-5e58-a972-815ccf92a7e0">18. Frank B. Salisbury et al., “Bios-3: Siberian Experiments in Bioregenerative Life Support,” BioScience, vol. 47 (1997): 575–585.

      TWO The Long March

      IN JANUARY 2013, American biologist and author Paul Salopek set off to trek around the world. He began his journey at a lake in the Great Rift Valley of Ethiopia, where remains suggest that modern man originated. Salopek’s goal, over a period of seven years, is to walk all the way to Tierra del Fuego— a region that lies the furthest from humanity’s birthplace—via the Middle East, Southeast Asia, China and North America. His planned hike is about 30,000 kilometers long (21,000 miles); he hopes to complete it in 2020. Salopek wants to retrace the path that humans have taken since starting out from Africa.

      Part of our emerging consciousness is an ever increasing awareness of our long march, how deeply rooted we are in the cosmos, the solar system, our planet and life. This awareness is not always present in our everyday lives, what with washing dirty dishes, chatting on social networks, or meeting deadlines. Part of the appeal and beauty of scientific research is to develop this awareness more thoroughly in ever greater detail.

      Modern-day people have brains that have been transformed by environment, long before people acquired the ability to change the environment. Nowadays, what we like or dislike, or fear or do not fear, or perceive to be or not, have much to do with the living conditions of our ancestors. These forebears include the squirrel-like Purgatorius that lived soon after the extinction of the dinosaurs; Eosimias, one of the earliest anthropoids that lived 41 million years ago; the chimpanzee-sized Kamoyapithecus that lived 25 million years ago, regarded by many researchers as the first hominoid and the last mutual ancestor before chimpanzees, that lived in Africa approximately 7 million years ago. This leads finally to the first hominids such as Sahelanthropus and Australopithecus that paved the evolutionary path for the genus Homo. Our lives today are linked by invisible threads to this past; each set of respective environmental circumstances, from the meteorite impact that doomed the dinosaurs, allowing for the era of mammals (who could otherwise have become the pets of highly intelligent dinosaur descendants) to the expansion of the savannah in East Africa due to natural climate change.

      Our biological constitution is, for the most part, an echo from the past three million years when the earth was significantly colder than it is today. A factor that contributed to this cooling process was the formation of the Isthmus of Panama three million years ago, which connected North and South America and interrupted the flow of warm water from the Pacific Ocean over to Africa. Atlantic currents were forced northwards, eventually leading to the formation of today’s Gulf Stream. The Himalayan mountain range also continued to rise, which rerouted Asian rivers to flow northward rather than south. Flowing into northern seas diluted their salt concentration: water that is low in salt freezes more quickly, which led to the glaciation of the Arctic region. The sea level sank during these periods to an average of 426 feet because the water froze.

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