), or if you grew up prior to the mid 90's your parents would get you together with other children, one of which would have chicken pox, and you would all get sick. One way of immunizing people is to use an attenuated vaccine which is a living, less virulent form of a pathogen. Attenuated vaccines are made by cultivating bacteria or viruses in the tissue or eggs of other animals. After several generations, the pathogen has evolved to survive in its new environment and is less pathogenic towards humans. At that point, the cultures are harvested and given to humans. They provoke a response from the immune system, but they aren't deadly. The desired effect is for the adaptive immune system to "remember" the pathogen and be ready to prevent future infection.
Attenuated vaccines are the standard way of immunizing people from polio, measles, mumps, chicken pox, the flu, tuberculosis, etc.
Polio killed 6000 Americans in 1916 and left 27000 paralyzed.
In Europe the vaccine reduced tuberculosis cases by 90%.
The measles was killing 450 people per year in the US prior to development of a vaccine. Now only those not eligible to receive MMR vaccines have been the only recorded deaths.
This is just three vaccines developed this way.
So the application of evolutionary theory has actually saved lives and lengthened life expectancy. How many lives has creation science saved???
And this is just one of the applications evolutionary biology has.
