The Changes in the Gene Pool Over Time

Each species has different characteristics which drop out it to survive in its particular habitat. These characteristics are carried in the genes, and those genes which vest the dog with characteristics which make it suitable to survive in a particular environment become the dominant genes in that population, ensuring survival. For example, the long legs of the maned wolf of the South American pampas allow it to see eat in the tall grass; shunting of blood to their large ears to collapse excess heat helps the fennec fox survive in the juicy deserts; the arctic fox changes its coat from white to embrown as the snow melts and it lives on the tundra until the next snowfall, and it has thick fur which c all overs the soles of its feet to reduce heat loss during its winter life in the snow.

As pets, dogs have been bred and interbred by humans over the years to produce desired characteristics (Natural History Museum, 2002). This is called conventionalised pickaxe because it does not occur internally. The interbreeding of different types of dogs has led to most(prenominal) of the 400 recognizable dog breeds today, and most of the breeds have been

Natural History Museum of Los Angeles County. (2002). Natural and artificial picking.

Bacteria become resistant to antibiotics through a natural selection processes (Natural Selection Made Easy, 2004). An original population of bacteria contains a mixture of individual bacteria with differing levels of confrontation to a particular antibiotic.

This variation is due to a variation in the genes in the individual bacteria. When these bacteria come in tactile sensation with an antibiotic, the least resistant ones are killed off first, and those with increasing levels of resistance live increasingly longer. If a patient stops taking an antibiotic before all the bacteria are killed, those with a high resistance to the antibiotic will survive and reproduce, lead story to a population of bacteria with resistance to the antibiotic. This is a possibility of natural selection.: those bacteria with the genetic makeup which allows them to survive the antibiotic will live to reproduce. This is what Darwin termed "survival of the fittest."

http://www.nhm.org/exhibitions/dogs/evolution/selection/index

produced since the 1850s. While breeds of wild dogs will change over time as natural conditions
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