Human genetic change is several orders of magnitude slower we have to go through a whole fifteen-year process of maturation before we can even think about passing our genes to a new generation. Each new generation opens up new possibilities for genetic innovation, either by new combinations of existing genes or by random mutations. For one, bacterial life cycles are incredibly fast: a single bacterium can produce a million offspring in a matter of hours. Bacteria and viruses evolve at much faster rates than humans do, for several reasons. This is an evolutionary principle that has long been observed in populations of disease-spreading microbes. It also greatly increased the lethality of the bacteria. The combined work of Snow, Whitehead and Farr resulted in Snows development of the ‘Ghost Map’ of cholera deaths and water pumps in the Golden Square district, and Snows use of that map in persuading the local authority to remove the arm from the Broad Street pump. cholerae circulating through the small intestines of mankind. “The contamination of drinking water in dense urban settlements did not merely affect the number of V.
0 Comments
Leave a Reply. |