Negative mutations such as chronic pain would normally get selected out of a species but because humans have become quite adept at survival we don't select out these traits as easily as a less intelligent species might.
Humans also have an exceedingly long lifespan. Is it even possible to perceive the effects of evolution on the human race?
Bacteria, on the other hand, have lifespans on the order of hours and reproduce at a much faster rate. They can also absorb DNA from the environment, transfer DNA to other bacteria and receive a literal DNA injection from a virus.
Bacteria, on the other hand, have lifespans on the order of hours and reproduce at a much faster rate. They can also absorb DNA from the environment, transfer DNA to other bacteria and receive a literal DNA injection from a virus.