“About 4 billion years ago, microbes appeared on earth and about 130 years ago the first microbe was discovered” (Crawford ix). Microorganisms are the simplest and smallest form of living things on earth and they are very powerful. Microbes can be used for ecological purposes, some are also pathogenic and others have helped in the medical field to create antibiotics. The author, Dorothy H. Crawford is Professor of Medical Microbiology and Assistant Principal for the Public Understanding of Medicine at the University of Edinburgh.
She is also the author of The Invisible Enemy: A Natural History of Viruses, and she was awarded an OBE in 2005 for services to medicine and higher education. Microbes existed on earth far before humans, and since microbes were discovered to be pathogenic, humans have tried to control the spread of diseases caused by them. In the book, Deadly Companions: how microbes shaped our history, Crawford explains how different microbes have shaped our history through epidemics and how humans have dealt with many of the diseases. She also explains how the microbes have evolved and shaped human history.
Black Death, smallpox, syphilis, SARS, and malaria are among some of the diseases she talks about and evaluates the impacts they have had on the evolution of the human race. Microorganisms are everywhere, they exist in every living matter on earth. Not all of them are pathogenic, in fact, most of them are useful and help shape the earth. For example, certain bacteria that help decompose the dead matter on earth. Most of the bacteria that exist on earth are not harmful to the environment, even though they are found in every place.
In the beginning of the book, Crawford explains that, before humans existed oxygen was poisonous to any life form, but bacteria discovered that using oxygen could help generate energy (Crawford 11). Alpha-cyanobacteria were the first microbes to use oxygen to create energy and use the mitochondria found in cells. Before bacteria existed oxygen was not seen as a valuable and useful thing, but after bacteria started using oxygen to produce energy, it became essential for living things. Without oxygen use today, living things would not survive. Also, this creates the relationship between plants, animals, and the environment.
For instance, photosynthesis was discovered from bacteria, which then came eukaryotic cells, through photosynthesis microorganisms obtained their energy from the sun and produced oxygen. In exchange humans expire CO2, which is used by plants. Crawford supports the idea that bacteria discovered this magnificent mechanism of using oxygen as an energy source for cells, which helped evolve the necessities of bacteria and later of eukaryotic cells. Crawford also emphasizes that microbes have helped shape the history of human beings by causing disease and making humans more susceptible to microbial infections.
Most of the diseases caused by microbes started in the Old World which is European countries. Then, when Europeans started coming to the New World they brought along diseases and microbes that caused the Natives to become ill. Some of the causes of the spread of the diseases were that Europeans would unintentionally bring microbes with them. Also, during the transition from hunter-gatherers to farmers created a door for microbes to exist. Soil contains many microbes that could infect the crops being grown and then cause disease to the people.
Since people were overcrowding and creating cities, there were unsanitary conditions because everyone was in one small place in order to survive. As Crawford points out, “With no facilities for waste disposal everything was thrown out into the narrow lanes that ran between the dwellings so that these dark, dank conduits became quagmires of mud, human and animal excreta and garbage, most of which ended up in the rivers that served as the water supply” (Crawford 82). Many of the diseases were acquired by contaminated water, such as Vibrio cholera, which is found in contaminated water from feces, and sea animals such as fish and shrimp.
Even today, these diseases can be seen in less fortunate countries and they do shape the human race in that place. It helps the people become more susceptible to such diseases because their immune systems can fight off some of the diseases easily. When epidemics spread they killed thousands of inhabitants which decreased the population. Crawford examines that when the Europeans came to the New World many of their disease causing microbes killed populations of Native Americans.
Their bodies were not used to many of the microorganisms introduced and they quickly died because the immune system of the Native Americans were not susceptible to the diseases caused by certain microbes, “The result was devastating 90 percent drop in the Native American population over the next 120 years” (Crawford 114). The death of many Natives due to disease helped the Europeans gain more power over the land and bring their customs, which has shaped the history of this country. If the Europeans would not have wiped out entire communities of Native Americans due to disease, then the U. S. would not be a western civilization country.
Microorganisms played a big role in destroying the Natives, Crawford talks about the diseases spread to the New World as smallpox flue, measles, dysentery, whooping cough, and meningitis. She argues that due to the “wiping out of their population their customs, culture and language were lost forever” (Crawford 118). This can be supported by Columbus Conquest in America, many of the population of Native Americans died because of disease transferred from Europe through the Columbian Exchange. Microbes have not only shaped our history by causing disease, but it also has helped distinguish between social classes.
During the great epidemics striking in the Old World, those who were in the higher social class, could escape death. Since they had more money they could travel far to not die. Crawford stated,” Of course the rich could escape the infection, as royal courts often did, by moving to the country for the duration of the plague in the city, and in contrast to smallpox, which devastated European royal families, this precaution seemed to have some effect against the plague since only one European monarch died of it” (88). This demonstrates that even long ago those fortunate enough took advantage of what they had to escape death.
On the other hand, the poor who did not have anything were the ones to suffer from the deadly diseases. It was also hard for them to obtain health care. Disease is still very prominent in those countries, such as in Africa they suffer from Malaria and they are not educated nor have the resources to prevent diseases. But also, countries that have the resources can provide their citizens with preventions, but the less fortunate countries cannot, so social class can also be seen not through individuals but also whole countries. Crawford analyzes that social class dominance can be observed by having the
