Chapter Twenty — Small World
A Short History of Nearly Everything – by Bill Bryson
Chapter 20 — Small World
- A healthy human adult has about one trillion bacteria living on his or her skin. This is about 100,000 bacteria per square centimeter of skin. These skin bacteria consume the approximately 10 billion small flakes of skin that an adult human sheds daily.
- There are also trillions of bacteria in and on our digestive system, nasal passages, hair, eyelashes, eyes, and teeth. Our digestive systems alone are inhabited by one hundred trillion microbes, of at least four hundred different types.
- Every adult human body consists of about 10 quadrillion cells, and plays host to about 100 quadrillion bacterial cells!
- Some of the many roles that bacteria play are:
- Processing our wastes
- Purifying our water
- Keeping our soils productive
- Synthesizing vitamins in our guts
- Eliminating alien microbes
- Converting nitrogen into useful nucleotides and amino acids
- Providing our atmosphere with oxygen (oceanic algae and tiny organisms produce 150 billion kilograms of oxygen every year)
- Bacteria are very prolific. Clostridium perfringens can reproduce in 9 minutes. At that rate, a single bacterium can produce more offspring in two days than there are protons in the universe. A single bacterial cell, with adequate nutrients, can generate 280,000 billion offspring in a single day.
- Any bacterium can take pieces of genetic coding from any other. Essentially, all bacteria swim in a single gene pool. Any positive adaptive change that occurs in one area of the bacterial universe can spread to any other.
- Bacteria can eat wood, wallpaper glue, metals, paint, sulfuric acid, and numerous other noxious substances. One species was found thriving in the waste tank of nuclear reactors, utilizing plutonium. Bacteria have been found in boiling mud pots, caustic soda lakes, deep inside rocks, in icy waters, and seven miles deep in the Pacific Ocean. A strain of Streptococcus was recovered from the sealed lens of a camera that had stood on the Moon for two years. Scientists successfully rejuvenated some anthrax spores that had lain dormant for 80 years in a museum display in Norway. Bacillus permians bacteria that were estimated to be 250 million years old were resuscitated. The spores had been trapped in salt deposits 2000 feet underground.
- It is estimated that if you took all the bacteria out of the Earth’s interior and dumped this load on the surface, it would cover the planet to a depth of 5 feet. Hence, there is probably more ‘life’ under the surface of the Earth than on top of it.
- Today the number of species of bacteria is about 5000, but this is still far short of the 26,900 species of algae, 70,000 species of fungi, and 30,800 species of amoebas and related organisms.
- Only 1% of all bacterial strains will grown in culture.
- In the 1970’s, a scientist named Carl Woese reclassified all living organisms into 23 main divisions. These were grouped into three new principle domains – Bacteria, Archaea, and Eucarya. He used the genetic sequencing of bacteria to make his divisions.
- Microbes account for 80% of all the biomass of planet Earth (which includes every living thing, including plants).
- Only about 1 microbe in a thousand is a pathogen for humans.
- Most of the most devastating bacterial or viral diseases that afflict humans (malaria, yellow fever, dengue fever, encephalitis, etc.) begin with a mosquito bite.
- From 1485 to 1552, a terrible disease labelled ‘English sweating sickness’ ravaged Europe, killing tens of thousands. The disease quickly ran its course and burned itself out. Being too efficient at killing a host is not a good thing for infectious organisms.
- A human body has some 10 million different varieties of defensive white cells, each designed to identify and destroy a particular sort of invader.
- Necrotizing fasciitis is a lethal disease in which bacteria essentially eat the victim from the inside out, devouring internal tissue and leaving behind a pulpy, noxious residue.
- About 70% of all antibiotics used in the developed world are given to farm animals, to promote growth or stave off infection.
- An Australian doctor discovered that many stomach cancers and most stomach ulcers are caused by a bacterium called Helicobacter pylori.
- There may be a bacterial component in all kinds of disorders – heart disease, asthma, arthritis, multiple sclerosis, mental disorders, cancer, and perhaps even obesity.
- There are about 5000 types of known viruses, causing hundreds of types of diseases.
- Viruses prosper by utilizing the genetic material of a living cell and using it to produce more viruses.
- Smallpox, a viral disease, killed an estimated 300 million people through the ages.
- World War I killed 21 million people in 4 years; the swine flue did the same in just 4 months. Almost 80% of American casualties in World War I came not from enemy fire, but from the flu.
- It is a great mystery as to why the 1918 flu epidemic was so incredibly deadly, when most influenzas are not.
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