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Course Hero. "A Short History of Nearly Everything Study Guide." January 18, 2018. Accessed September 20, 2018. https://www.coursehero.com/lit/A-Short-History-of-Nearly-Everything/.
Course Hero, "A Short History of Nearly Everything Study Guide," January 18, 2018, accessed September 20, 2018, https://www.coursehero.com/lit/A-Short-History-of-Nearly-Everything/.
Bryson details the discovery of hominid fossils. Prior to 1891, only a few fragmentary fossils had been found. Then Dutch anatomist Marie Eugène François Thomas Dubois traveled to Sumatra with the goal of finding the earliest hominid remains. What he found was the first evidence of Homo erectus. This species of human had a larger brain than any ape.
In 1924 Australian anatomy professor Raymond Dart was studying the fossil of a child found near a village in South Africa called Taung. He realized it was from an earlier period than Homo erectus and named it Australopithecus africanus. Other scientists, however, refused to believe the fossil was human and insisted it was an ape. At this point there were four named hominids: Homo heidelbergensis, Homo rhodesiensis, Neandertals (Bryson's spelling), and Dubois's Homo erectus. However, this changed rapidly. Canadian amateur paleontologist Davidson Black discovered Sinanthropus pekinensis, or Peking Man, at Dragon Bone Hill in Beijing, China. Gustav Heinrich Ralph von Koenigswald found a group of hominids called the Solo people along the Solo River at Ngandong in Java, and more new fossils continued to be found. By the 1950s there were over a hundred named hominids.
In 1960 American anthropologist F. Clark Howell proposed changing the classification to include only two genera: Australopithecus and Homo. That system did not last. Today there are approximately 20 types of hominids, and in Bryson's words, "almost no two experts recognize the same twenty." The problem lies largely in lack of evidence. Fossils of early humans are not "distributed evenly through time and space."
The current understanding of human evolution is for the majority of human existence, the species was part of the same ancestral line as chimpanzees. Approximately seven million years ago the australopithecines emerged. This species lived and moved around on the open savannah, leaving tropical forests behind, and they dominated Africa for five million years. The most famous australopithecine is a specimen known as Lucy from approximately 3.18 million years ago; yet, the skeleton is only about 20% complete. The australopithecines were initially believed to be direct ancestors of Homo sapiens. However, later discoveries of older specimens confused the matter. Lucy—who probably didn't walk upright very well—might have been an "unsuccessful side branch."
The australopithecines have raised questions about why early hominids transitioned to bipedal (two-footed) locomotion in the savannas. Walking upright requires a strong pelvis with, for women, a narrow birth canal that makes childbirth painful. It requires birth of a baby with a small brain, requiring long-term infant care and male-female bonding. Bryson suggests it was cooling weather that forced early hominids out of the forests into the savannas.Approximately two to three million years ago, there may have been up to six different hominid species in Africa. Homo habilis—"handy man," named in 1964—marks the first appearance of the Homo line. They are characterized by a 50% brain size increase and the first real use of tools. Homo erectus were the first hominids to leave Africa, "some time well over a million years ago." They were strong, with "the drive and intelligence to spread over huge areas." There is also evidence for meat-eating and care for the sick. However, even with Homo erectus and present research, controversy continues over the correct identification of fossils.
The history of the human species is characterized by a lack of understanding. While researchers now have many more fossils to work with than in the 19th century, the understanding of human evolution is still unclear because of the egos of the scientists in the field, the difficulties in fully understanding the fossilization process, and the sporadic nature of the finds that occur. Bryson explains much of the problem is "a shortage of evidence." Not enough fossils have been found to accurately fill the gaps and flesh out the picture of human evolution. When fossils are found, often they are not complete and just represent a skull or bone that may not be comparable to the other skeletal portions that exist for a certain species. As a result, comparisons are difficult across different fossils. Moreover, the history of human evolution is subject to different interpretations based on the preferences of different scientists.
The story appears to be during the early period of human evolution, a number of hominids were coexisting on Earth. However, the exact relationships between these species is still unclear.
He ends with the fact there is more genetic variation between "a zebra and a horse, or between a dolphin and a porpoise" than between chimpanzees and humans. The human species is "still 98.4 percent genetically indistinguishable from the modern chimpanzee."