Course Hero. "A Short History of Nearly Everything Study Guide." Course Hero. 18 Jan. 2018. Web. 21 July 2018. <https://www.coursehero.com/lit/A-Short-History-of-Nearly-Everything/>.
Course Hero. (2018, January 18). A Short History of Nearly Everything Study Guide. In Course Hero. Retrieved July 21, 2018, from https://www.coursehero.com/lit/A-Short-History-of-Nearly-Everything/
(Course Hero, 2018)
Course Hero. "A Short History of Nearly Everything Study Guide." January 18, 2018. Accessed July 21, 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 July 21, 2018, https://www.coursehero.com/lit/A-Short-History-of-Nearly-Everything/.
In this chapter Bryson discusses the conditions necessary for the rise of life on Earth. He notes in 1953, graduate student Stanley Miller was one of the first individuals to attempt to synthesize life—that is, to produce it by combining various elements. However, Bryson tells readers, science is "much further away from thinking we can" synthesize life today. Miller was able to produce amino acids, the chief components of proteins, which are synthesized by living cells. But amino acids are fairly easy to synthesize, and proteins are not. In fact, in the case of proteins and DNA and of the chemical compounds necessary for life and the membranes that encapsulate them, it is unclear how they evolved when each requires the other to exist. Bryson remarks, "It is rather as if all the ingredients in your kitchen somehow got together and baked themselves into a cake." Not only that, he adds, but the cake would be one that can divide to produce more cakes. Given the complexity of producing life, Bryson says, proteins must have evolved. This in itself is not miraculous because many molecules in nature have the tendency to assemble and replicate.
While the main materials necessary for life are not rare, their formation requires certain conditions. Recent recalculations of the age of life on Earth, approximately set at 3.85 billion years, suggest life arose, in the words of scientist and writer Stephen Jay Gould, "as soon as it could, was chemically destined to be." At the same time, life began only once. Bryson calls this the "most extraordinary fact in biology." There might have been many life forms that lived briefly, but only one reproduced, passing its genetic material on to another being in a process sometimes called the Big Birth.
Carbon isotopes and the mineral apatite found in a rock 3.85 billion years old in Akilia Island, Greenland, are the oldest marine sediments ever found and evidence for the first emergence of life on Earth. Bacterial organisms would have been the first life forms to appear, followed two billion years later by blue-green algae. The algae absorbed water molecules and hydrogen and released the oxygen as waste in the process of photosynthesis. From this increasingly oxygenated world, algae began to trap microparticles of dust and sand and to form structures called stromatolites, which were like living rocks. Over time, the algae brought the oxygen in the atmosphere up to levels seen today, and a new kind of cell arose, the eukaryote. This cell had a nucleus, which made complex life possible.
Continuing with the theme of what biological scientists still do not understand despite breakthroughs in other fields, Bryson notes there is still no understanding of how to create life. The lack of understanding of a process so fundamental to existence has resulted in some scientists believing perhaps the instigator for life is extraterrestrial in origin. However, the majority of scientists believe life did not arise elsewhere, but from Earth itself.
Humans do now know roughly when life came into being—approximately 3.8 billion years ago—with fossils found providing evidence for this life. However, scientists do not yet understand the full context of the Big Birth. Differing suppositions of the chemical compositions of the primordial ocean lead to quite different scenarios for the creation of organisms capable of reproduction. Bryson nonetheless continues to convey the sense of wonder humans should feel at their own existence.